Some vendors may not have Monterey testing completed with their applications, and some printer/scanner vendors may have dropped support for their devices even before Big Sur. I suggest in addition to the 32-bit applications that are not supported on Catalina or later, that you check your third-party application vendors, printer, and scanner vendors for their Big Sur and Monterey release schedule and commitment. Look before you leap, and don't let the new operating system write to the Time Machine drive that you last used on the old System prior to the upgrade.
These are standalone full operating system installers that only share the requirement for an APFS formatted startup drive. Otherwise, there is nothing in Catalina, Big Sur, or Monterey that the subsequent operating system depends upon from its predecessor.