IMO the TV needs to go on the wall where you have the piano ans I would suggest you look at Besta from Ikea for a great way to have TV some storage and a bit of display to make that a feature wall This is one way of putting the pieces together but you can do many ways to fit your style and needs Put solar shades on the window to control glare, heat and UV rays and keep the view . The piano could maybe go on that stair wall depending on the size . Then I like a sofa and 2 chairs for furniture you might even be able to do 2 soafs and 2 chairs depending on the style of sofas . get those pieces how you like them and then come back and we can help with the rest . Post everything to do with this space here in comments DO NOT start another post

I agree. I would put tv on other wall where piano currently is and piano by stairs. maybe a sectional and a swivel chair or 2 sofas . I’ll attach my very sad looking sketch!

I think I would put two large chairs with a table between under the big window, the couch, or even a sectional on the wall to the left of the large window (with two windows in it, I think) with the other leg of the sectional parallel to to the wall with piano. If you don't want a sectional (and who would blame you?) I'd get another two chairs or a loveseat for that side. I'd leave the TV on that wall where you have it, but I'd put it in a cabinet. From the photos and the size of the couch you have, it looks like a pretty large room. I would definitely NOT put the furniture up against the walls, but pull it in several feet, maybe even yards and put a big rug for at least the edges of all the furniture to sit on. I can't tell for sure, but the room looks large enough that you could have two separate groupings of furniture....I wouldn't do that myself unless you have a lot of parties. If you have a ton of space along walls, I'd buy some cabinetry or bookshelves. Or build some, like we do!

Alternatively, if you don't want a family room centered around the TV, which I completely understand, turn the couch to face the large window (with a sofa table and two lamps right on the back side of the couch), and put a loveseat (or two chairs and a table) on the left wall and two chairs on the other side, near the stairs. Put a low bookshelf under the big window. Put the TV in one of the corners in a cabinet, probably to the left of the large window. You won't get glare that way, at least. A large window is a lovely focal point for a grouping.

I think your TV is mounted on the wrong wall

That wall should be used for a foyer table with mirror, console, bench and lamps

The opposite wall should be used for a larger screen TV for this room

You can select a sectional or sofa with two side chairs.

I assume the piano will stay in the room.

You mounted your TV too high in the room. Keep these dimensions in mind.