Go to this site:
https://ipsw.me/product/Mac
select the type of Mac, then select the .ipsw file for the operating system you with to restore.
NOTE: the links are to direct downloads from Apple servers not a third party,
Follow this article:
Revive or restore a Mac with Apple silicon with Apple Configurator 2 - Apple Support
and when the "DFU" image appears in the window, simply drag the .ipsw file onto the window. At that point you will be prompted to do a revive or restore, Select restore. IMPORTANT NOTE: Restore will completely wipe everything from the Mac.
Once complete, restore your data from your backup you did before installing Monterey.