Try using a regular TV cover (so you have a ready-made base and don't have to sew it yourself) and sew it around with an acoustic foam or fabric. Something like this plus this. Choose lightweight materials for paneling, and when choosing the cover, also pay attention so it doesn't damage your TV screen from the inside. Such a construction turn out budget-friendly and could really work
Covering a TV behind your speakers?
I just read on another site a guy asking what difference it would make covering his TV while playing music. His picture shows a decent system but it must be in the basement. It can't be more than 12' wide. No sound treatments to be seen. I'm going through a divorce and will have to move to a much smaller one person house. I've been lucky for 30 years having my expossed basement listening room, 20' x 24', naturally almost perfect as far as sound goes. I have been reading here and other sites trying to learn about treatments. Never heard the TV thing before. A few people responded to the guy's post that they hang drapes over the TV. I would think since current TV screens are not glass but whatever they are made of now they wouldn't cause a problem. Looking forward hearing from the experts here.