Yes, it could be a gag; but one where the butt of the joke is people's assumptions about the character instead of the character's identity.Xeno Goku Black wrote: ↑Fri Aug 12, 2022 7:08 pm 2. An opportunity for a gag.
Them making Jiren gay would fulfill what purpose for the show? Is it merely to tick some diversity box? So nothing to do with the show itself then?
Have Jiren return with a guy at his side and have everyone act shocked when he introduces said guy as his boyfriend. Have Jiren ask why that's shocking then have Goku or someone else remark that they just assumed Jiren was into women, then have another character remark how silly that assumption is- perhaps Whis since he's at least coded gay and that's the type of all-knowing remark he would make ("It seems people here make silly assumptions" or something like that).
It would be in the spirit of Dragon Ball's tendency to subvert audience expectations while making a joke about gay people where the joke isn't "ha ha he's gay (and that's weird and creepy)" but rather "ha ha, people assumed this big strong guy is straight when he isn't."
Hell, you could even use it to put a bow on Jiren's post TOP character development: After he decided to embrace friendship he unexpectedly ended up finding love as well.
That's the most Dragon Ball way to do it that wouldn't be offensive.