Comment by hamdingers
2 hours ago
You have an old Steam.app stub, download the latest one and rosetta will not be necessary.
If you had rosetta it would be able to self-update to the new universal binary, without it you have to do this one update manually.
I downloaded from here and I instantly get a pop-up about requiring Rosetta.
https://store.steampowered.com/about/
Odd if true. It's clearly a universal binary, not sure what's going wrong for you.
$ file steam_osx
steam_osx: Mach-O universal binary with 2 architectures: [x86_64:Mach-O 64-bit executable x86_64] [arm64]
steam_osx (for architecture x86_64): Mach-O 64-bit executable x86_64
steam_osx (for architecture arm64): Mach-O 64-bit executable arm64
CMD+I on Steam.app says: "Application (Intel)".
% file steam_osx
steam_osx: Mach-O universal binary with 1 architecture: [x86_64:Mach-O 64-bit executable x86_64]
steam_osx (for architecture x86_64): Mach-O 64-bit executable x86_64