Why does it have to be cheap? What if I want a killer panel without all the bs?
> Use a small "air mouse" for control
An alternative is something like 'unified remote' on it, then you can even type from your phone without any pain.
> A browser with VPN for streaming in some cases.
There is a missing piece for me here. A magic 'send my PC browser tab to this other PC connected to the TV' button. Not sure if something like this exists. It would be ideal to send all the browser context with cookies etc so that you are logged in too and can just start playing whatever you found on PC.
Any for of cast is not an option, rendering has to happen on the TV PC box.