Is there a way to off the Apple TV device and return to regular TV viewing?

If you mean return to input from cable tv (non-internet streaming), then just change the input for the TV using the TV remote. If the Apple TV box is idle (not actively streaming, e.g. just having the Home Screen on), then it will go to standby (sleep) in a few minutes.

Or, if your TV provider is supported, add their app to Apple TV as well.

Could you elaborate slightly? The Apple TV is for streaming a variety of channels. Are you considering using an aerial or dish again as opposed to streaming?

I switched from that older process of annoying cable boxes a while ago and don’t find i miss that awful slow user interface adverts anymore.