x32 is a different (possibly badly designed) Linux kernel ABI for programs running in 64-bit mode on regular x86-64 processors, but with 32-bit pointers. It has nothing to do with Intel or Windows.
Realistically, Windows is the platform keeping 32 bit code alive, in the form of all those legacy binaries. MacOS and Linux have moved on. So if you design something new for 32 bit that can't be used by Windows, it's DOA.