Camouflaging opening behind the TV-ideas?

You can make a deep frame for your TV to sit in. Remove the holes, spackle and paint when you move.

I would paint it the same color as the wall to make it less noticeable or put up a curtain the same color as the wall to blend in. Good luck.

A barn door would look cute there. That is a pretty dated feature, and you could always install shelves, too. But a barn door would be easy to remove and patch holes. Otherwise a large, simple piece of artwork could work, as well.

Hang a simple curtain on the wall. Pick something that will blend with the wall color.

Probably a simple large painting would work.

You could either shelve it or put a blind in it to match the one in your window. Pulled down to make it look like a false window.

I have a similar problem. Thank you for all your suggestions! I never knew what to do with this gaping hole.

I would put up a stretched canvas painted your wall color there. I feel it would blend better than a curtain or pallet wall covering -anything that causes more distractions.

I just ordered a large gallery stretched canvas from here very recently -pretty amazing prices —much better than craft stores or amazon.

https://www.dickblick.com/products/blick-studio-cotton-canvas/