You have to install 32bit driver libraries to run steam. On Debian/Ubuntu/Mint it's libnvidia-gl-455:i386 package.
I couldn't run steam after upgrading to 455, and noticed it was because CUDA and some other unofficial display driver PPA in my sources.list was blocking simultaneous 64bit and 32bit install. After removing those, I could install the package again.
I couldn't run steam after upgrading to 455, and noticed it was because CUDA and some other unofficial display driver PPA in my sources.list was blocking simultaneous 64bit and 32bit install. After removing those, I could install the package again.