Either Mask of the Phantasm or LEGO Batman
I remember that was on DCU, I wanted to watch it but it git removed before I got the chance.
Batman vs Robin was epic, I honestly didn’t think it would adapt the court of owls storyline.
Completely unoriginal, Mask of the Phantasm! A big honorable mention to The Batman Superman Movie: World’s Finest.
That’s a hard one, since I like so many. But I guess Flashpoint. I like when I get to see the multiverse in action. Thomas Wayne as a grittier broken Batman was just too good not to enjoy.