I think you misunderstood what's happening here. The steam client was historically 32 bit but now will only be 64bit.
Everything 32 bit runs on 64 bit systems, but 64 bit apps won't work on 32 bit systems.
Windows started supporting 64 bit in 2001, and really any modern game is probably 64 bit already since 32 bit applications can't address more than 4gb of RAM (not that anyone can afford more than that right now)
To me I'm shocked anyone at all is on a 32 bit os, phones don't even really have 32 bit anymore and in the world of personal computers it would be more work to find 32 bit hardware than 64 bit hardware.
Most likely that 0.1% will just have to wipe their computers and install 64 bit windows which their hardware probably supports already and they somehow accidentally installed the 32 bit option.

https://takeout.google.com/
Export your photos with take out
Then use immich-go to import
https://github.com/simulot/immich-go