You can stretch SteamOS's capabilities out a little bit, but I wouldn't get too serious about it. The OS partition(s) don't have a lot of space, everything gets bounced back to start with every OS upgrade, and between SteamOS upgrades its Arch signing keys get pretty badly out of date.
I dunno how long it takes for the Deck's particular drivers to upstream to "real distros". Arch may already be there, Debian is probably not.
You can stretch SteamOS's capabilities out a little bit, but I wouldn't get too serious about it. The OS partition(s) don't have a lot of space, everything gets bounced back to start with every OS upgrade, and between SteamOS upgrades its Arch signing keys get pretty badly out of date.
I dunno how long it takes for the Deck's particular drivers to upstream to "real distros". Arch may already be there, Debian is probably not.