Different boot times for dual Windows 11 installations on same PC

Hi folks. I've successfully installed and isolated two installations of Windows 11 on my PC. One for work (Pro) and one for games (Home). I've moved the EFI partition to its own dedicated drive and removed the original and things work flawlessly. I've disabled Fast Startup, and disabled the drive for the alternate OS in Device Manager and they appear to be completely isolated from one another. The strange thing is that when selecting which OS to start on the bootloader, the original (work) installation starts up very quickly whereas the second (games) installation restarts the PC and takes much longer to load.

I can't understand why because the EFI/bootloader partition is completely isolated on its own drive and both OS installations are on fast M.2 NVMe SSDs so I can't account for the difference. I've double-checked that Fast Startup is disabled on each, there is no hibernate file and neither are encrypted or have any substantial difference in configuration.

Could anybody provide any insight into this? I'd appreciate it.

Thanks.