A downside to your suggestion might be that when you stand at the front in the hallway, you look at the side of the TV… and you have the stove at your back… hmm… that's so difficult!
I don't see seeing the TV from the side as a problem at all. Or do you still have an old tube TV?
The important question first is why the fireplace should be exactly where you positioned it. Is there perhaps another place for it?
Put the piano on the left wall; it’s a nice eye-catcher from the hallway and you won’t linger there so long that it could become uncomfortable like on the sofa. Also, the walkway should remain clear, since you also have a small door in the corner at the back.
I would place the sofa in the room with its back to the piano. Normally, I would prefer the corner next to the sliding door to the kitchen, but that doesn't work together with the large window and TV.
I would do it this way too: piano on the bedroom partition wall as a welcome focal point. Structure the spacious room with the backrest of the sofa.
I would do the glass door to the hallway with frosted glass or cover it. That makes it cozier.
I would refrain from this angled position. It doesn’t look good… such a lost corner in the middle of the room created by the sofa doesn't bring good karma (bad energy, Feng Shui).