The Steam Client Beta has been updated with the following changes: 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. Game Recording Fixed errors copying to clipboard or exporting H265 videos on systems with a NVIDIA 50xx series gpu.
It’s not illegal if you’ve bought it.
Does it use steamworks drm? You could download it on a new PC and move it over if not.
It probably still works in a VM on under compatibility layers like Linux with Wine/proton/whatever, too.