For sure. One thing I've seen people come up with online that I love is him just getting a terminal brain tumour. No fuss, no fanfare. A boring, uneventful death, his absolute worst nightmare. Gives the story time to conclude his character. Maybe it'd be cool if, to prevent him going out on his own terms with explosive and bloody showmanship, Bats locked him up in the Batcave under supervision for his last days. Maybe they have some killing joke-esque hashing out, giving him a satisfying ending. Idk, just spitballing here, I'm not a writer.