Help with System Preferences

I have recently updated my 2015 iMac to the newest macOS Monterey. I hadn't used the computer in a few months due to having another job. I am unable to open anything inside of my system preferences. The Users and Groups gives me error "Preferences Error, Could not load Users & Groups preference pane". This also happens if I try to go into my Security & Privacy. I have been having a few issues out of my iMac and wanted to check a few things and I am unable to do so. I've tried deleting a few guest accounts that show up in the terminal when i run heatherm.@Heathers-iMac ~ % dscl . -list /Users | grep -v _

daemon

heatherm. (This is Me and should be the main account)

nobody

root

sadiew. (profile I recently created for my daughter)

I did purchase this computer from a reseller about 2 years ago but haven't had any issues out of it until recently. I do not know what the other three accounts are on this computer and they are not options when the computer loads up. The computer is running alot slower than normal and some of my programs are not functioning properly (as I know I can update them and will work that out later) but I just can't access some of the information I'm wanting to see in my System Preferences and I do not like this at all.

Any help would be greatly appreciated.

[Personal Information Edited by Moderator]