We use Sophos as our Endpoint Protection Solution and from what we've gathered, third-party solutions alongside built-in OS protection can interfere with each other on a lower level. Sophos recommends disabling other solutions: Information on installing Sophos products alongside a competitor's software
Deferring updates to our devices so that they do not upgrade to macOS Monterey is one thing but that can't be the solution for the long term. And we continue to use Sophos due to our environment having been setup already with a purchased license, Windows management, and familiarity with the service.
So what would be the best move here?