When I upgraded my Mac’s OS a while back, I also had concerns about software compatibility.

From what I’ve read on operating systems (https://operatingsystems.info/), upgrading to Monterey might mean you’ll need to move up to Indesign for full compatibility. However, the latest Indesign version can surprise you with stability improvements over earlier releases.

If you’re wary of bugs, maybe consider waiting a bit after the OS upgrade to see user feedback on Indesign versions.