On real X64 hardware you can’t be in 64-bit mode without pageables,Well, to exact there are two variants, one with PEI being IA32
(OvmfPkgIa32X64.dsc) and the other with PEI being X64 (OvmfPkgX64.dsc).
The latter does page table setup and switch to long mode in ResetVector
But, yes, on both cases the firmware volume with PEI+DXE ends up being
loaded below 4 GiB.