Update:
Four days now, and nothing's crashed. On top of the stuff in the OP, I've used Soundtoys stuff, SSL, Melodyne (sparingly and tastefully, of course, and only because it was an emergency π π). All fine.
The Waves updater is behaving a little weirdly, but I think that's just the updater because they've put out multiple updates for it in the last few days so they must know something's wrong, and the plugins that I've used have all worked with no problem π€·ββοΈ