I’m running everything that is proprietary (Steam for example) on a second user that is a not an admin account. Heroic and the like are installed via Flatpak that is sandboxed. Sometimes games contain malware, even on Steam. If something goes badly wrong, I purge that second user.

A shop that’s been around for ages and is very generous when it comes to adding extra stuff to a big order - our local group is ordering there for many years now: https://www.ixsoft.de/cgi-bin/web_store.cgi (see “Fan-Artikel” then “Aufkleber” - yes, the website looks dated, I know)