How do I make a TV blend into the wall?

Unless you purchase the higher end tv that morphs into a mirror or painting, there is not a lot you can do. How about an entertainment center with doors to close when not in use?

I think you are looking for this HOmetalk project:

https://www.hometalk.com/diy/decorate/walls/tv-wall-decor-a-pottery-barn-inspired-diy-gallery-wall-36331392?

You can frame 🖼 out using wood and create your own canvas, or use and existing piece of art work.

I would frame it with artwork, photographs. Use the same frame colour throughout. Then the TV will blend into the background.