Not sure if it's up your alley, but Outward was (for my son and me) great and fun co-op experience.
It's an open-world survival RPG, that although made by Canadian devs, firmly falls under Eurojank category (that is, ambitious A/AA projects that have plenty of fresh ideas, but not AAA polishing - like Gothic back in days). Haven't played it for quite a bit, in the meantime they've released a lot of additional content and improvements, so sooner than later I have to check it out again, most likely with my other son (my wife would love to play it, but she's really bad with gamepads).