Tons of software meant to run on 32-bit hasn’t been updated to run on 64-bit natively.

32bit only Linux apps are basically non-existent, anything with the source available and maintainers would have been ported at some point in the last 2 decades, otherwise they have very specific technical reasons for being 32bit only (like OBS iiuc), the source has been lost somehow, or it's a proprietary program where the company has no interest (e.g. Valve with Steam)

In fact I think Steam might really be it.