He unfortunately hasn't really had the opportunity to make enough of a real impression to comprehensively evaluate, and it now seems he might never get it, which is wholly the fault of Warner Brothers for not having faith in the franchise and changing their plans.

Also, this is forgetting Cesar Romero, who totally counts as he was in a theatrically released movie.

I remember Leto saying he was really disappointed a very large amount of Joker scenes he filmed for Suicide Squad got cut from the final movie. I heard Birds of Prey will apparently have some flashbacks of Harley and Joker that use said cut material, but Leto getting another chance at playing Joker in a new movie seems unlikely at this point.

It's also unlikely Phoenix will return since the whole reason why he took on the solo Joker movie is because it's NOT attached to the DCEU. He turned down the role of Dr. Strange because he didn't want to be tied down to a film franchise with many planned sequels and crossovers, but accepted Joker because he was told it'd be a one movie deal and that's exactly what he wanted, a superhero or villain role that is just one movie.