Oh and another point: on Debian every package you get is Debian. On Arch the stuff in AUR is not Arch and is not supported by Arch, it’s unstable experimental stuff and you take your chances with it.
In practice, generally, the AUR stuff trends to mostly work fine but it’s never guaranteed. It can and it does break spontaneously from time to time.
This applies to ALL Arch-based distros. So if you plan on counting on AUR to supplement your app needs, please reconsider.
Debian stable has ~100k stable packages included. Arch has ~15k bleeding edge packages included and ~80k “varies wildly” in the AUR. It will not be the same experience.
Debian with Steam and other popular desktop apps (like LibreOffice and Firefox) installed from Flatpak will be a much more reliable experience.