Start with an area rug or mat, to draw the seating area together. If you don't want a "rug", there are some nice patterned vinyl mats that are easy to keep clean with toddlers around. Perhaps also add a floor lamp next to the chair or a corner of the couch to give it a "reading corner" kind of feel.

There’s a lot going on.

First off I’d work on layout.
Does current set up work for you?

I might put the dining table along the window wall and the desk where the table is.
But we don’t know what else you have and what rooms adjoin to what...

Then I’d pick a style. You have a mix of modern and more traditional. Which way would you like to go? What style do you prefer?

I’d then get some more pieces to match the style you choose. Like a coffee table.

Maybe curtain panels with more color.

Art

Rug

...

Thank you so much, these are such a great ideas. I want to replace the table under the tv so it matches with the rest of the furniture too. Any suggestions?

Like mentioned above, with only these photos and no more info, we're just guessing. But I think what you have is already a great start. Everything seems to go together nicely and I don't know if it's possible to get a better arrangement than the one you have which gets a lot of stuff in without looking jumbled. I'm kind of impressed!

A rug to define the seating area is a good suggestion and probably the best and easiest thing you can add.

If this is a major walkway, a coffee table might not work--the ottoman you have off to the side probably serves that function when needed, right?

I can't see the TV table well but it doesn't seem to be fighting with anything. I might turn the desk to face the dining room but I'm not sure if there's room.

This seems very tidy for a place with 2 little ones. Suspiciously so. :) Did you clean up for the photo or do you have a good system in place already? If you don't have a system, it might be worth finding a way to get some storage into the room. If it's always this neat, then no need. (A dinosaur here and there is fine.)

Hi Fori,
I do pick up the toys every night before going to sleep so the place is ready for work and online learning ὡ2.
The only issue that I have turning the desk facing the living room is that all the cables will show up. 
Beside the dining table is the kitchen. Please see some more pictures below.
And again thank you for all the feedback.

You might look into the FLOR carpet tile system, you can easily deal with kiddo spills and such.

Or chiliwich rugs, which are more like large placemats, easy to clean.

https://www.flor.com/

https://www.chilewich.com/store/

Do you like the existing paint colors? Are you allowed to change?

I would suggest:

- new cabinet for under the tv, and move the tv lower, it seems a bit high.

- different art behind the dining table, larger.

- art over the sofa

- rugs (see above links)

- some bright pillows

Jean

Hi Jean,
Thank you for your comments. This is new paint we just got it to match the furniture.  So unfortunately can't change at the moment.
Would you suggest a particular color for the rug?

Let me take a look around. Need to find one with hints of the wall color and the furniture...something cheerful.