Spirit Island is a complex and thematic cooperative game about defending your island home from colonizing invaders

yes

Yes, it's good if you like fairly difficult co-op games.

There's a third party campaign mode called "Spirit Archipelago" that a friend of mine and I have been playing for ~6 months which has helped us play something like 70 games so far.

Yes, this game is amazing. Incredibly based game.

It's extremely good from a gameplay perspective and decent from a politics perspective. I do think the way the dahan are depicted is kind of stock "indigenous people" as opposed to having any clear culture of their own, but then again it's a tactics boardgame so they were never going to go that deep with it.