This is true. And it’s also why I always recommend downloading steam through their website. They distribute their own Deb directly, and it auto updates.
Flatpak version is also okay but if you want to use a secondary disk then you need to know how to use portals (or the Flatpak configuration tool that I can’t remember the name of).
I think there is a value you can put into a /sys file to fix this. Had the same issue on my k10 keyboard. (the fix was easily findable on their forums)
This might help in the future in case you setup a remote mount for backups in the future. Look into using systemd’s automount feature. If the mount suddenly fails then it will instead create an unwritable directory in its place. This prevents your rsync from erroneously writing data to your root partition instead.
I also like lutris. But it being “for games” doesn’t do it justice I think. It is basically just a wine environment manager. It advertises as being for games but it should work with just about any windows executable.
This is probably the reason why most distros will have the home directory on a separate partition. To easily allow you to keep your most important data when reinstalling or switching to a new distro.