Can't boot to macOS after changing power supply!

I had to change the power supply of a desktop that otherwise had been booting into WIndows and macOS.

The computer boots to the text version of Open Core, previously it was the graphical interface. Why the change?

If I choose mac OS (Sonoma and Ventura are on separate NVME drives) the picker shows "OK" but macOS will not boot.

The only OS that will boot is Windows. I installed an APFS reader in Windows, all the macOS files appear intact.

I checked the BIOS settings, they appear unchanged? Although the NVRAMfix kest is in the EFI pressing spacebar does nothing. I'm not sure what resetting the NVRAM would do for this anyway. I also booted with a known good USB key but get the same "OK", then nothing. I waited up to ten minutes with the "OK" showing but macOS will not boot.

Any clue?