Stuck on boot at around a quarter done?

I recently updated my late 2013 iMac 27 from Catalina 10.5 to Monterey. It ran fine for a few days, i leave my mac on sleep as i tend to come to it at random times Whilst it was running I had no issues whatsoever. I came to it yesterday locked in sleep mode, it then wouldn’t restart at all and eventually had to unplug it and plug back in. It booted after around 10 minutes stuck on the Apple Screen and then ran incredibly slow and laggy. I turned it off planning to try and sort it out today and now I can’t even get past the apple screen on startup. Ive tried booting it from the EFI partition and the EFI external drive i originally used. I am stuck on this screen both times. Any one had similar issues? 32gb Ram, 1Tb HDD, 3.4gz i5