Through the large window/sliding door element and the requirement for sofa/TV, it becomes difficult, but surely there will be a solution.
Viewed from the entrance (hallway):
The piano goes on the left wall; it is a nice eye-catcher from the hallway and one does not linger there long enough for it to become uncomfortable as it might on the sofa. Additionally, the walkway should remain clear, because you still have a small door in the back corner.
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 does not work with the large window and TV. So a long sofa, possibly with an ottoman for the feet. In front of it, the coffee table. View of the stove and TV, sideways out to the large window, view into the garden. A bit in front of the sliding door then two cozy, not too tall armchairs with a small table in between. Nice view from there, a good spot when you have guests. Two armchairs are not such a blockade like a sofa; the entrance in front of the sliding door should not be blocked. The TV then on the wall or on a TV stand, depending on taste. Important to me would be a rug under sofa/armchairs/coffee table that separates and anchors that area from the rest of the room.
And place a tall cabinet or a tall shelf somewhere so that the room does not feel too flat. Cozy lighting through table and floor lamps etc., and done.