The setting with the most impact is probably to not give notifications for agreements - this cuts down a lot. You can also unfollow (though I prefer the above first if you haven’t done it yet as unfollowing can lead to missing some potentially important notifications).
The can also use this tool from @pisum:
https://jumear.github.io/stirfry/iNat_observations_updates.html
or check out some of the ideas in this current thread:
https://forum.inaturalist.org/t/what-to-do-about-many-notifs/44599
Edit: sorry I see others have suggested this, only saw one response to this initial post with the question, not the subsequent ones.