Hey,
I stumbled on this thread after loads of debugging.
My current situation is that I'm one of those stuck on a fastboot loop after running some system updates and leaving the phone idle for some time.
I've tried flashing both 2019 and 2020 images, they seem to work successfully but the phone just reboots to the same old fastboot screen.
When trying to perform any unlock commands via fastboot-cli, I always get denied. None of the flashing commands work or slot changes.
I am not sure if the EDL flashing is even successful as I don't really get actual feedback of changes beyond the