Sorry for the late response. I ended up following what Prant suggested:
You can update the phone just fine with unlocked BL. Those devs have no clue what they're talking about. Just take care to disable all modules, fully unroot first via Magisk, reboot! Then you can take the OTA update like normal, you will be unrooted of course. So just reroot via booting patched boot again on desired firmware.
This did the trick for me and I updated just fine.
The problem is NFC Payments with Google Pay aren't working. I'll try to figure it out