I'm sharing in the hope this helps someone in a similar position to me. As I use my PC pretty much exclusively for gaming, I wanted a seamless experience much like a console.

I currently have Playnite set up to provide a console like interface. It's a fantastic front end which keeps all your games in all launchers in one place.

So my PC is in my office, and is connected to my 32" monitor. However, I also wanted to game on my couch where my main 55" TV is. So I drilled through the wall and have a 5m ethernet, HDMI and USB extension cable run through the wall into my main TV (cable managed and tidied away of course).

In order to have a seamless experience, I purchased "Controller Companion" from Steam. This launches on start-up. From this, I can use the "Back A" shortcut which changes my screen output to second screen only which is my TV in my living room. "Back Y" changes the output back to first screen which is my office. I couldn't get round having to log in every time I boot up. Fortunately, Controller Companion provides a keyboard facility by pressing L3 on the controller. I can then enter my passcode with ease. So I no longer need a keyboard. When Controller Companion is active, and I am not in Playnite full screen, my controller also works as a mouse. So no need for a mouse either.

Playnite launches on boot into full screen mode with the "Playnite Modern UI" skin. Mouse visibility is turned off so everything runs though the controller.

Unfortunately, Controller Companion doesn't seem to work well with Windows/Xbox PC Games. So the "back and start" button shortcut deactivates Controller Companion which resolves this for me. Pressing this shortcut again reactivates it providing keyboard and mouse access once again.

Extension wise, I have Duplicate Hider, Game Pass Catalogue Browser, Ludusavi (For Save Game Backups), Game Acivity, SuccessStory, Splash Screen and Image Cash Size Saver installed.

Playnite launches and shows games filtered by Installed. I have all my 3rd party clients linked to the platform as well as games not associated with launchers and emulators. So I can browse my library if I want to download any other game in my library.

Honestly, the best experience I have had gaming in a LONG LONG time.

Hope this helps. If anyone has any suggestions or ideas to make things even better, please don't hesitate to share!