I've Googled and searched this forum, and the few mentions of difficulties between Audition 22 and MacOS Monterey were made some time ago. Adobe's known issues and solutions page for Monterey does not mention Audition at all, so may I assume I can upgrade to Monterey safely?
I've found at least one reference to it running audition without difficulty, and coupled with the general lack of posts about this, I'd say that it's very likely indeed to work fine.
Many thanks, Steve!
Great! Thanks so much, Euan!