That's correct, although 32-bit processes on a 64-bit operating system (as are still supported on Windows and Linux, and were supported on macOS until Catalina) can effectively have 4GB.
Back when I was still using Windows, you could boot the 32-bit OS with "/3GB", which would make the kernel/user split 1GB/3GB instead of the original 2GB/2GB default - but it was optional and explicit, because quite a bit of software failed; I would guess that changed with time, but likely a similar "/4GB" switch for 32-bit apps on 64-bit OS would also expose assumptions about the address space layout ...
Back when I was still using Windows, you could boot the 32-bit OS with "/3GB", which would make the kernel/user split 1GB/3GB instead of the original 2GB/2GB default - but it was optional and explicit, because quite a bit of software failed; I would guess that changed with time, but likely a similar "/4GB" switch for 32-bit apps on 64-bit OS would also expose assumptions about the address space layout ...