Along with what Tulsadiver said, if you're caught in a bootloop you can also boot into Safe Mode (hold volume down button when you see the Google letters until the phone vibrates) and then reboot normally and your mods will be disabled but not removed. You can then remove the offending mod but keep the rest of them.Thanks for your help and suggestions. I didn't intend to do the update without some prep but the phone updated itself overnight and the update installed in a reboot. Normally I follow the standard procedure and remove the mods prior to updating. I wonder if I delete Magisk and the mods now if it would work? Maybe I'll try that and let you know.