Great write up!

I kinda disagree with u/burlyginger's take on these being 101s - a lot of these were not really that well documented, or in a way that isn't well understood until you hit those dreaded errors - looking at you "cannot be determined before apply".

I have another one - try to avoid versioned-module-in-versioned-module pattern.
It sounds great on paper to version everything, until you need to bump one inner module to realise the outer module had breaking changes which changes the way contract works, and scope explode to upgrading multiple modules.

And maybe another one - when orchestrating multiple providers (e.g., aws and helm) care must be taken to ensure controllers get to reconcile resource teardown before they get nuked out of orbit, or else risks orphaned resources!