Beau is Afraid was the last one I recall. I think it was mostly the latter half of the movie where I started to get a bit confused and needed the ending explained to me.
What movies made you look up some kind of explanation afterwards? I feel like I have done it several times in the past for more surreal movies but can’t think of any other examples.
It can also be a TV show.
Les Revenants (The Returned). French series about a village where deceased residents start coming back from the dead. The ending was good, but there was a lot of ambiguity about what happened and why it stopped. I went down the rabbit hole and found some compelling reddit threads that tied it up rather neatly.