While SteamOS is open-source and everyone can build one for themselves, it is only officially supported on Steam Deck. They promised to release a generic version of it targeting more devices in the past, and this post hints that that day is closer.
I have tried Bazzite before and understand its appeal. I am an ex-Arch user so I prefer the system to be as minimal as possible. Fedora fits my requirements just right and Bazzite does not seem to bring anything to the table that I miss from Fedora.
Fedora Kinoite. I like KDE, atomic distros and the fact that Fedora is the only (at least that I know of) distro that has proper SELinux implementation.
I also play games on this system, so having newer kernel and Mesa versions help.
NewPipe
UFW, by default, blocks all incoming requests. This means that SSH (port 22) is blocked already. Then, if you need to, whitelist (ALLOW) ports that you want to expose to the network. For example, I have ports 1714-1764 whitelisted for KDE Connect and everything else is blocked.
I suspect you have installed either Lutris or Steam through flatpak.
Try installing both using the same method or install MangoHud both as a flatpak and a system package.
Also, I recommend enabling MangoHud with ‘MANGOHUD=1 %command%’ instead.
KDE Plasma got a once-a-year notification that asks for donations a few months ago, which shows up in December.