If it was just my husband and I it would be fine the way it is. with children it’s a huge safety issue because if they stand on the couch they can go down the stairs. It’s driving me crazy to say the least. I feel others might look at the room differently than I would and would have a better idea

take the lamp with the yellow shade and set it on your end table. It will give you a feel for size. Im not sure you can go much larger on the end tables might start to get stuffy. Also, do you have floor out lets? IMO, not at pro. But I think that whole back wall could be better sorted. maybe a sofa table behind the could be a better place for lamps? OR maybe a long narrow console table on the back wall. move your art around and put lamps there?

Get out the painter's tape and tape out a rug like this on the floor. It should be a minimum of 12" from the hearth and I like them to slip under the front 1/3 - 1/2 of the sofa. Things look more grounded if the rug extends past the ends of the sofa by a foot or more. Tape that out. Take a new photo and let's see what standard rug size is closest to your measurements.

Don't know what the heck those numbers mean on the floor plan. You'll probably have to "float" the seating arrangement in the middle of the room. A couch will be in the middle, with the back of it hugging the straight dash line. To either side of it (allowing of course for room to get around), will be an upholstered chair. Add curtains, side tables, art, rug etc. See if you can get local art. Art is a very personal thing. Take your time and get pieces you love. Carefully consider the amount of space you have to move around. I personally like more space than stuff, but that's me. How many people do you usually have sitting in this room? If you entertain a lot, consider additional seating with poofs and/or mini ottomans that people can sit on. Another option for extra seating is putting slightly upholstered straight back chairs in the corner for company. I'm personally not keen on Bobs furniture - I'm just giving you a general idea. Measure twice, buy once! https://www.mybobs.com/furniture/living-room/chairs/p/20061608001 In my opinion, gray is kind of trendy. You may want to think of a more classic color. Sherwin WIlliams is my fav, but there are a lot of paint companies out there. https://www.sherwin-williams.com/homeowners/color/find-and-explore-colors/paint-colors-by-family#/active/color-wall/section/sherwin-williams-colors Sherwin Williams has brochures in their stores that show how to coordinate everything in a room with a certain color. I worked in customer service for many years. If you get a nt so helpful person - ask for someone else or go to a different store. In my opinion, there's no excuse for bad customer service.