how long should a reinstall of Monterey 12.5 take?

i have a 2019 iMac and was having trouble with Monterey 12.4 not running the Finder properly, i.e not all disks would appear on the desktop, TimeMachine wouldn’t work, programs would stall on loading, couldn’t change between users, Finder would be ‘not responding’ and would not relaunch, etc. Even if Finder was working it wouldn’t shut down or restart. If I was lucky enough to change to the other user the same problems would appear.

So after advice from a number of you smarter folks I got a new external ssd drive, got 12.5 installed and migrated the files from my old internal drive to the new one. Did this because it had been over a month since the last real backup and I didn’t trust it. Additionally it would, when I tried to do a backup, tell me there was 0 room on the 3TB backup drive then the next time I tried it would tell me 961 Gb. Either way it wouldn’t backup. TimeMachine would almost always, when it would open, show the daily & weekly snapshots.

Subsequently I was having the same Finder problems. So I decided before I went to bed last night to boot to Recovery and reinstall 12.5. Now, about 12 hours later, and in the middle of typing this (thank goodness I have an iPad) it’s finally finished.

I’m submitting this in case someone has some thoughts as to what might be causing my problems. Maybe I’ve gotten lucky this time and I’ll have to come back with an apology for wasted your time. Thanks in advance!