why not just keep an HDMI cable and a laptop near you and hook it up when you want to watch something? It can basically do everything these little tv boxes do and more, you probably already own a laptop capable of this and the hdmi cable, and you don't have to worry about ads. The toughest part might be if you have 4k videos to drive the display.

Usually comes down to convenience for my family members.

Any recommendations on a voice remote control for a TV-connected PC?

PC also needs to support TV power on/off and input switch via HDMI CEC, as well as a launcher to easily switch between the 2-3 streaming apps we use with our remote control.