My iMac restarts

Ask about After Market SSD >> disk0 - CT2000MX500SSD1 2.00 TB (Solid State - TRIM: No)

There are reports appearing on the ASC Forums regarding failed installation of Monterey on older Qualifying Apple Computers. In most cases this is related to having a NON Apple Original internal drive ?  

The EFI Boot ROM included in Monterey is verifying for Original Apple Drive and if not found , may Balk or fail to upgrade to Monterey. 

Reports indicate the EFI BOOT ROM is Required to Flash the Computer and is a  requirement for a Successful Monterey Installation.

Best guess, is you have 3rd party RAM, and it may (total guess) be failing.

If you are getting these panics on a regular basis, try removing the 3rd party RAM and just use the Apple provided RAM to see if the problem goes away.