@SSUPII
@sopuli.xyzInvisible only doesn;t show the notification, but play time is still counted on your profile. If you check a profile and you see the latest game's play time increasing over time but they offline, it means they invisible.
It's per game.
Right click a game (or press Start in BigPicture/GamingMode), select Properties. Go to the Privacy tab, and there you can hide the game from everywhere but yourself. The game will only be visible in your own library when logged in, and people won't see you playing that game when you run it (you appear Online but not playing anything, your nickname in friends list remains blue). You also make the game invisible in your profile, both on the main page with the play time and on the full games list.
You can also do it before purchase, now every time you put a game in the cart you are asked if you wanna make it remain public or hide it.
If we talking about modern Android, good to know. I used to run a launcher on a modded Samsung Galaxy Young (CyanogenMod11) that had a fixed notification option to prevent Android from killing it (the device had 512MB of RAM).
You used to be able to just create a fixed notification and Android would never kill the app. This is not the case anymore?
Would be a bit of an adapter chain hell as you get only 1 usb-c port to work with, and you need both that and a DisplayPort cable