Living area incorrectly designed, ideas for changes?

I would install a wooden panel, possibly also as a room divider (often a relatively short piece is enough). Place the TV straight on the wall. A coffee table also in wood. I also think wood is missing, warm colors for the wall, as a carpet, sofa cushions, etc.

Someone was faster, that’s exactly what I meant!

The back of the upholstered suite already looks (for the time being) like a room divider and can be quickly repositioned. Different lamp.. one that hangs lower over the coffee table and does not glare.

I would find one like this suitable .. Artemide Tolomeo Sospensione Decentrata

I would place such a room divider. Otherwise, I find the ceiling lamp too puny - as a result, the air space looks so bare and the curtains hung under the ceiling also emphasize the empty area of the lintel above the window. On the floor it looks full, in the ceiling area oppressively bare.

Regarding color....I happened to buy the Farbenfreunde from Alpina by chance (it was on sale and looked quite good). It's actually children's room paint, but the shades are very warm. Caterpillar green in the living room, hummingbird green in the bedroom, and fish blue in the kitchen :D. There's also elephant gray.....

To make it cozy, you won't get around a room divider. I've never seen such a large room look cozy without it being divided into several "niches".

A cozy layout inside would be important to me.

So with the backrest facing the room or dining table

Then you usually don’t sit cozily… a wall at your back gives security and a sense of safety.

Otherwise, I find the ceiling lamp too puny -

Yes! Not just the lamp. The problem with larger rooms furnished with small furniture without statement pieces is that they automatically feel cold, because the free wall surfaces dominate.
Then corners should be combined with curves.
The carpet size is fine!
A large round pendant floor lamp that spreads out over 2-3 meters would be good. Light at half the room height. For the ceiling lamp, only a small spotlight. Or use a ceiling connection for a big balloon lamp that does not hang in the center.
I find the table and sideboard too small. The TV looks cold. Replace the two pieces of furniture with heavier wooden ones. It doesn’t have to be too rustic, but a contrast in wood with grain emphasizes the modern sofa.
Wall color in dirty, grayish tones. Sand, gold, bottle green… Curtains in the same color.
For color/furniture, gold/sand/natural wood would fit.
I would also replace the carpet. In terms of color, it is more of a “nothing” and therefore does not ground the room.
It is a very beautiful room with a lot of potential.

Then you usually don't sit cozy... a wall at your back provides security and comfort.

In that situation, I would simply try all possibilities. It could well be that towards the open door everything is anything but cozy. We once had a similar situation; I could never relax on the sofa because it was against the wall and we were practically looking into the large room, which I always found unsettling. We then actually placed the sofa with the backrest into the room, and we found that much cozier, as the view was no longer so open and the space in front of the eyes was visually limited. However, I wouldn't plan it that way from the start.