Curate, connect, and discover
Stole this idea from @lordbasilsnek because I had no idea what to post on here at first, so go check them out cuz their headcanons are pretty cool too.
He is banned from the Batkids yearly hide and seek game due to his powers. He and Cass (Who was banned simply because she was too good) decide to be commentators. Duke does most of the talking.
After his parents were jokerfied, Duke learned how to braid his own hair. Once he moved in with Bruce he got the chance to grow out his hair. It throws half the batkids off when the morning after their patrol instead of the afro he's had for the past 7 months he has cornrows with beads in colors he and Cass picked out the day before.
Almost monthly Duke and Jason argue which side of gotham has the best pizza. Jason's is some shitty crime alley pizza place that gave him a free slice every now and again. Duke's is near his parents apartment. It's black owned. Its the greasiest shit you will ever put near your mouth. His mom hated how unhealthy it was. He and his old friends would eat there every Saturday afternoon anyways. These arguments are one hair away from getting physical because both of them are too fucking stubborn to admit they can both be right.