I do the same thing. My PC is hooked up via HDMI to a receiver which goes to the TV via HDMI. I use VNC on my phone to remote control it. It works well. The phone’s touch screen functions as a mouse and you can pull up the phone’s on screen keyboard to type. My wife is extremely non technical and does fine with it. Usually we just use the browser to watch ad-blocked YouTube or unofficial sports streams.

Elecom Relacon, the only wireless input device worth owning.