based on what wouldnt they have magical mystical zoan abilities? The artificially created devil fruit at least has the magical cloud ability. So i dont see any reason for an artificially created dragon to not have any mystical powers. BUT, there is another point to be raised: There could be different types of dragons with different characteristics.
edit: especially because the PH and oneshot dragons were not eastern dragons like kaido is.
If oda made it canon, why wouldnt it be relevant?
Sure, oda would want to save it for kaidos reveal. but that still means we currently dont know that option is a thing in the one piece world. And therefore, kaidos powers originating from a df ability is more likely.
Wait, are we talking about momo or the punk hazard one?
The punk hazard dragons were western styled dragons that flew via the bird method of wings. They also only breathed fire.
Momo's devil fruit is probably directly inspired off of Kaidou, the dragon from punk hazard was probably just some lizards mutated.
Anyway there is another possibility: they could turn into humans, but were butchered while in dragon form, oof.
Anyway the point of ryuuma vs a dragon is that it would be made well before kaidou was even perceived as a concept, also I don't see any reason to believe that the dragon couldn't have turned into a human anyway, just because it didn't in the one shot. If oda ever does a backstory of it again and goes with the kaidou is a dragon thing, I could see oda bringing that up.
Monsters (Ryuuma's thing) was released in 1994, one piece was released in 1999. I think it's fair to assume that when he was making Monsters, he wasn't thinking "this series will fail, but my 1999 series will succeed, and when I get to chapter 1000, I'll reveal this about dragons", heck, if that one shot became a series, it might have even been brought up even, and we'd be reading Monsters rn instead of One Piece.
IT just feels outrageous to claim that just because the 1994 series that predated One Piece as a concept even, didn't include it, that it can't be so.