~ thanks for posting... Mr. Macintosh FTW! i tried many different reboots over the past few days and happened to see your post just before giving up and erasing the HD to do a "clean install". A couple notes that may help others:
when booting to Safe Mode, be sure to enter the same user / folder name when "creating a new user" -- not even sure why this is needed to get to Safe Mode, but if you use a different name you will not have Admin rights and will not see your existing apps and data.
Safe Mode no longer allows File Sharing, which includes mounting an External HD -- again, why... since backing up files is something you actually want to be able to do in Safe Mode. ***?
I was able to get to Google Drive via Safari in Safe Mode (but possibly only when i correctly created the "same" user as in #1) -- this allowed me to back up some files, as needed
when following Mr Machintosh's instructions, i went ahead and deleted all the files in the /private/var/folders/ -- this was presented as an alternative and was much faster than the find command with the -delete option specified
it seems like i may have had to reboot twice for this to work -- initially thought it didn't, then went back in Recovery mode to confirm the delete worked... then BOOM the subsequent reboot worked!
I actually tried to install Monterey from Safe Mode -- hoping that would work, but still got stuck on the Apple logo. So this fix still worked and i am now on 12.0.1.
Thanks again, @Mentorofmen