In any 32-bit operating system, the physical address space
is limited, by definition, to the size of a 32-bit value
No… the /virtual/ address space is limited to 32 bits. It’s possible to have more /physical/ memory than this, and it’s even useful if you want to run more than one large process at a time. PDP-11s did this, AFAIR.
I don’t know enough about Windows or Intel architecture processors to know whether this is possible in that environment, though.