In short:
General
The Steam client is now 64-bit on Windows 11 and Windows 10 64-bit.
- Systems running 32-bit versions of Windows will continue receiving updates to the 32-bit Steam client until January 1, 2026.
Hopefully a 64 bit Linux Steam client will follow soon, that way I can get rid of all the 32 bit packages I currently have only installed for the Steam client.
Keep in mind that a huge percentage of games are actually 32-bit so you may still need the libraries. Games made the transition to 64-bit much later than other software. 32-bit games were still being made just a few years ago. Of course, if you aren’t playing Linux-native games, that won’t matter much.
I don’t play any native Linux games, I have found those are not as well maintained as the Windows version so I played them all through Proton.
Same here 
Still, finally. It’s amazing that they’ve dragged their feet for so long. Especially since I presume the MacOS version has been 64bit and ARM compatible since the introduction of Apple silicon.
Linux SteamRT3 Beta
- The Steam for Linux client can now be run inside a Steam Runtime container. This will help the Steam client provide a more consistent experience across multiple distributions. This is the same technology we use for Steam games.
- The SteamRT3 beta client is distributed alongside the regular beta client. You can opt-in to the beta client via the ‘Use experimental SteamRT3 Steam Client’ toggle in Settings->Interface.
> * The SteamRT3 beta client has been updated to 64 bits.- Please report issues specific to the SteamRT3 beta in the Beta Forums or the steam-for-linux issue tracker.