monterrey not installed after popup said it was.
installed big sur about 18 months ago, considerable slow down in starting mac mini (late2014) and in operation. About a month ago the audio left. Decided to upgrade to Monterey. Installed Monterey after several hours received popup stating upgrade and installation was complete. Restarted mini. Time to restart, including the 3-4 restarts that would happen after programs ceased to operate, until able to comfortably have programs function for about an hour. This has been the average start time since installing big sur. Has been as long as 3 hours after a power outage. When I check the preference overview it shows bi sur as the operating system not Monterey. The software update module regularly shuts off stating a disconnect happened. Just ran the software update module and it now states that there is an upgrade to Monterey available and asks to upgrade. Any suggestions on how to remedy these situations?