AFAIK they still aren't shipping an actual ARM64 version of Steam, making it difficult to actually use those (unsupported) ARM builds of Proton. That article is 5 months old.

You can use it really easily on Android devices through apps like Game Native and some of the more powerful Android gaming handhelds have support for Steam through Linux distros like Rocknix and Armada OS.

Not officially, but it's publicly available for download.

https://interfacinglinux.com/community/sbcsoftware/native-st...