I have an M1 Max MBP. My current circumstances mean that I need something portable. I'm homeless, I don't have anywhere for an iMac (as funky as they are - and I would really rather like a purple one). And I agree, Monterey is horrid. I have been trying to update to 12.6 ever since I got the notification in SysPrefs it was available. Safari updated no issue. I click 'update now', scroll down and agree to the EULA, I get the wheel for about 10/15 secs and then I'm back at the 'an update is available for your Mac' screen. Lather. Rinse. Repeat.
Nobody else uses this MBP but me, so there are no other accounts. I have rebooted, but I'm still going round in circles. If anyone's a clue why it's being obstreperous, please enlighten me.