Downgrade from CalyxOS Android 14 to FPOS

Hi all, how can I correctly downgrade from CalyxOS Android 14 to FPOS that is Android 13?

I have currently the bootloader relocked.
I reqd somewhere that In order to downgrade I could via fastboot and of course after unlocking bootloader but only flash with a OS that has same or newer security patch.

Someone can help?
thanks

It is at the moment. But I think A14 will likely be coming soon to the FP5 so if that’s your only motive then I wouldn’t bother. Likely a lot of trouble for little gain.

The security patch will be another dissuasive factor.

thanks for answering but I was looking for someone who has the same necessity or might have it in near future and can share the experience or the correct procedure in this case