What is on the front wall (to the right in your drawing)? Are the units cm or inches? I don't see the problem, other than that you wish it were larger, but I might be missing something int he details here. Does the TV have to be where drawn?

Put bookshelf on stairway wall. Put tv in middle of long wall. Put cat tree in corner where bookcase is now. Float couches facing each other - one with back to window. Put couches close enough so you can have an intimate conversation. Typical error in design is placing couches to far apart to have a conversation.

I’m glad you found the trampoline suggestion funny. :) I thought it was fun. But then, when I thought about it last night after I posted it, I thought, ”Yikes... I think I’ve really been on Houzz waaaayyy too long... 😂 I agree that it really comes down to what you are most comfortable with. Your comfort is the most important thing. So if you are comfortable with the loveseat with back to window and tv in the current position, definitely - why not. You could just leave the tv where it is and not go through a whole thing of converting the closet, etc. So yes, lower it a bit, if you can. And if you wanted to fill the space below tv a bit more, one idea could be some kind of plant stand under it with one tall plant or a shelf style unit with a couple of small plants on it, etc. Another layout you could consider - if it is possible - is to float the loveseat with it’s back to the closet, leaving enough room for reclining, and put the tv in this area. This way you are facing the window and not sitting with your back to it. And you have a number of options for the tv setup in this arrangement. You could use a mobile tv stand/console with wheels, and this would give you a lot of flexibility for placement - either in that corner or you could roll it over to be more centered in front of window, etc. These wheeled consoles are very convenient, and come in all kinds of styles these days. Or you could possibly use some type of corner console there. And as another option you might be able to just use a floating shelf style console. Depends on what style console you prefer and what would work best for you there. And if you decided to use a stationary console, you could wall mount the tv in that area and use some type of angling extension arm, to give you flexibility to make viewing adjustments. All types of arms available, depending on your needs and preferences. If you didn’t want to put a door on the closet right now - as one idea, you could put a folding screen in front of closet, and it would be a backdrop to the loveseat - if you can put loveseat in front of the closet. Could also be a nice look. I don’t like to promote glass coffee tables - plus for you end tables or mobile C tables, nesting tables, etc. would work better than a coffee table with your recliners. But just wanted to show the screens with sofa in background look, and this screen above, in setup with glass table, is another nice artistic screen, so I threw it in. :) But you can use any type of screen in front of the closet. And that would still be an option for you, regardless of where you decide to place the loveseat. All types of styles available. Sky is truly the limit. :)

Here is Idea Board. Of course you would do two sofas, two swivel chairs and two recliners etc. 12 x 15’ rug.