Seems like it's too dry. If excess water able to come out from pot hole, then you shouldn't worry about overwatered. Give it more water. Rock on bottom is good for drainage. Liquid able to flow in any direction, escape out from the pot, but solid only moving vertically down. That's how rock on bottom work, to let only water out, not the soil.

The brown on the leaves is likely from overwatering.

Rocks at the bottom do not provide extra drainage. It’s a myth and it’s very sad someone at a nursery would be so misinformed.

Does the pot have a drain hole?

Sun through curtains is just as good as no sun at all.

Itll grow best right up in front of your brightest unobstructed window.

These links will help you understand more about your tree and how water behaves in containers.

https://www.gardenweb.com/discussions/1476078/ficus-trees-in-containers-iv?n=223

https://www.gardenweb.com/discussions/2842847/container-soils-water-movement-and-retention?n=8

If you attach the plant to the window the plant will love it.

Dave, do you have any link about scientific experiment to proof that using rock on bottom of the pot is a myth? Try use aquarium or transparent glass pot and look the water movement ... it's help drainage, you'll see the difference.

Fiddle leaf figs need INDIRECT sunlight! Which means a bright room but not in the path of the sun! In one of your picture there are rays on the leafs and that will cause sunburn on the leaves! Fiddle leaf figs are notoriously finicky!

Where do you live, Esladis? Not necessarily looking for a city, but geography plays a part in whether certain aspects of device can be specific, or must remain general due to insufficient info. You might consider adding something like my tapla(Mid-MI z-5b-6a) to your user info. If I have a question or need advice, the person replying can give consideration to where I live and tailor advice accordingly.

Your plant is suffering from an inability to move enough water to satisfy its most distal parts. This can occur from under-watering, over-watering, or a high level of dissolved solids (salts) in the soil from fertilizers and the solutes found in tapwater. It can also be a combination of a high level of salts and either over or under-watering. A significant drop in relative humidity from what the plant was conditioned to can also be an exacerbating factor, but we don't have enough info to determine that. A 'tell' would provide that info.

If you start using a 'tell', you won't have to guess at whether of not your plant needs water. I saved the following from another of my replies:

Using a 'tell'

Over-watering saps vitality and is one of the most common plant assassins, so learning to avoid it is worth the small effort. Plants make and store their own energy source – photosynthate - (sugar/glucose). Functioning roots need energy to drive their metabolic processes, and in order to get it, they use oxygen to burn (oxidize) their food. From this, we can see that terrestrial plants need air (oxygen) in the soil to drive root function. Many off-the-shelf soils hold too much water and not enough air to support good root health, which is a prerequisite to a healthy plant. Watering in small sips leads to a build-up of dissolved solids (salts) in the soil, which limits a plant's ability to absorb water – so watering in sips simply moves us to the other horn of a dilemma. It creates another problem that requires resolution. Better, would be to simply adopt a soil that drains well enough to allow watering to beyond the saturation point, so we're flushing the soil of accumulating dissolved solids whenever we water; this, w/o the plant being forced to pay a tax in the form of reduced vitality, due to prolong periods of soil saturation. Sometimes, though, that's not a course we can immediately steer, which makes controlling how often we water a very important factor.

In many cases, we can judge whether or not a planting needs watering by
hefting the pot. This is especially true if the pot is made from
light material, like plastic, but doesn't work (as) well when the pot
is made from heavier material, like clay, or when the size/weight of
the pot precludes grabbing it with one hand to judge its weight and
gauge the need for water.

Fingers stuck an inch or two into the soil work ok for shallow pots, but not
for deep pots. Deep pots might have 3 or more inches of soil that
feels totally dry, while the lower several inches of the soil is 100%
saturated. Obviously, the lack of oxygen in the root zone situation
can wreak havoc with root health and cause the loss of a very
notable measure of your plant's potential. Inexpensive watering
meters don't even measure moisture levels, they measure electrical
conductivity. Clean the tip and insert it into a cup of distilled
water and witness the fact it reads 'DRY'.

One of the most reliable methods of checking a planting's need for water
is using a 'tell'. You can use a bamboo skewer in a pinch, but a
wooden dowel rod of about 5/16” (75-85mm) would work better. They
usually come 48” (120cm) long and can usually be cut in half and
serve as a pair. Sharpen all 4 ends in a pencil sharpener and
slightly blunt the tip so it's about the diameter of the head on a
straight pin. Push the wooden tell deep into the soil. Don't worry,
it won't harm the root system. If the plant is quite root-bound, you
might need to try several places until you find one where you can
push it all the way to the pot's bottom. Leave it a few seconds, then
withdraw it and inspect the tip for moisture. For most plantings,
withhold water until the tell comes out dry or nearly so. If you see
signs of wilting, adjust the interval between waterings so drought
stress isn't a recurring issue.

Al

Besides Al’s post, this thread is full of misinformation.

“Fiddle leaf figs need indirect light.”

Untrue. This is another one of those Internet myths.

All Ficus would prefer direct outdoor sunlight. Leaves grown indoors cannot handle that light load, but the plant can easily be acclimated.

An indoor tree grown in full view of the sun is going to have tighter internodes, will look much fuller and will also put on more growth than one on the other side of the room.

Gudang, I’m not going to spend any time going back and forth with you again, sorry. Please do a little research as to why rocks or pebble in the bottom do not help with drainage and actually impede it.

Dave is correct. Ballast, used appropriately doesn't really improve drainage, but it can very efficiently limit the amount of excess water an otherwise overly water-retentive soil CAN hold. Using material like pea stone or similar types of gravel simply causes water to perch in the soil above the well-intended "drainage layer". E.g., if you have a soil that supports 4" of perched water, at container capacity in a pot filled with soil only, you would have 4" of 100% saturated soil at the bottom of the pot. If you add a gravel drainage layer 3" deep at the bottom of the pot, you would have 3" of well-aerated gravel, with 4" of soil 100% saturated with perched water resting above the drainage layer. Above that, there would be soil that isn't 100% saturated. A gravel drainage layer, unless the size of the gravel is no more than 2.1X the size of the soil particles, does nothing more than limit the amount of soil available for root colonization. More about ballast here.

Al

The rock function is to increase surface area where water able to escape from the soil. With rock, soil surface on bottom side isn't flat, it's just mimicking planting in ground. Soil is solid, it's moving down only, but water moving in any direction, escape out vertically and horizontally. Without rock, the way water able to escape from soil is only from the pot hole. Using rock, pot with 2 holes work like pot that have 5 holes..

Ficus lyrata leaves able to live both direct or indirect sunlight, but only leaves that grow under direct sunlight able to survive sunburn. If the plant growing leaves indoor and you bring it outside or get direct sunlight, brown spot will appear on some of its leaves.

Adding large particles to media DECREASES surface area, which is why water perches (in soils capable of supporting perched water) above gravel "drainage layers". Water that would normally move downward in soils perches above "drainage layers" because with the decrease in surface area comes a decrease in the sum of the force of adhesion in the "drainage layer".

Al

Al I don't quite follow you. The bigger particles the better? Particles should be the same size?

Nope, irregular shape of rock actually INCREASE surface area since soil that contact with free air are increase. Remember that if you don't put rock, surface area where water able to escape from soil is only from the POT HOLE, not full diameter of the pot.

The bottleneck of water movement in pot isn't on vertical movement, but horizontal movement. When you're using ballast, you practically remove the bottleneck. With ballast, you're only dealing with vertical movement because on bottom of the pot, water flow freely horizontally toward the pot hole. Same argument apllied that 5 holes on bottom of the pot is better than only 1. Both have same functionality, avoid long distance horizontal movement. Perched water is horizontal movement problem, not gravity or capillary matter. It won't happen in ground where water able to go vertically down freely without necessity to move horizontally, even if the same rules of natural force counted. There's no perched water if you remove the slowest movement on pot culture, which is horizontal movement of water through the pot soil.

If there's rock on bottom of the pot, it's like you have many holes that are very close one another, reduce long distance horizontal water movement greatly, just like pot that have many holes.

This post on how to tell if your Fiddle Leaf Fig is healthy may be of help to you!

Six Ways To Tell if Your Fiddle Leaf Fig Tree Is Healthy

Hmmm - I find quite a few statements and
correlations I would disagree with in the article Claire links to, even
such a short piece.

Al