I didn’t relate to anyone in the movie (that I can remember) and I still loved it.
I really enjoyed it because of the immersion. I just thought it was good story telling and excellent acting.
I didn’t really take the movie to have any deeper meaning. To me it was the telling of one version of the joker’s origin story, one that is more grounded and realistic.
I was confused about him being Batmans brother. Is that canon now, or was it just in one of the marvel multiverses?
He confronts Wayne in the bathroom at a party/fund raiser, IIRC.
His mother used to work for the Waynes and hints towards this throughout