Sounds like you already have a solid plan.
If you have any old laptops or desktops you could convert those instead of using a Pi, but the Pi will work wonders as long as it’s not going to be a 4K TV. Your only real concern here is making sure whatever device you use is able to output video at the TV’s resolution and display hertz.
You’ll probably have more difficulty finding a TV that isn’t a smart TV, than finding a home theater device that is capable of streaming nowadays.
Nah, just swap it out for a Boeing.