Apple will not allow Installing an Older Version ( Monterey ) over the Top of a Newer Version ( Ventura ).
To downgrade back to Monterey from Ventura will require Wiping the Drive clean of Ventura.
That will then allow installing the Older Version of macOS Monterey.
Really do suggest doing at least Two Time Machine Backups each to Operate Drives Before attempting this action.
Using Time Machine Backup
In the next link 0 be very creation you choose the Type of computer this will be performed on.
There Methods for Intel Computers and Apple Silicon M1 / M2 computer.
The 2 Methods are very different
https://www.howtoisolve.com/downgrade-macos-ventura-to-macos-monterey/