Booting Debian/Ubuntu

[huesie]

I'm familiar with UEFI boot of Debian/Ubuntu on Intel/AMD but how do I use this UEFI to UEFI boot to Debian on RPi5 hardware please?

If I start from the RPiOS image (it's not UEFI as far as I know) - can this be converted to boot from UEFI? Or is there a way to boot Debian from this UEFI or (as I suspect) is there a simple way?

I'm familiar with Debian on lots of SBCs e.g. Sheeva/DreamPlug/Cubox and I could probably get this working with a lot of handcrafting trial-and-error but how are others doing it and is there a simple way please?

My main objective is to get REFInd to act as a UEFI boot manager so I can boot multiple O/Ss.