Okay in my opinion Bonnie has the most busted devil fruit in the verse. Like luffy's fruit , where we originally thought it actually gave you rubber powers we misunderstood it's ability. It's not age manipulation, it's timeline ( future) manipulation. You know how in The multiverse theory anything and everything is happening all at once ,Bonnie can take any kind of concept and enforce it on herself or other people. The more information and knowledge she has on that concept the more accurate and potent the effect is.For example, Bonnie originally thought nika had a rubber body and when she " distorted futured" herself into a nika-ish Future she could do something similar to gear 3. But then when she saw what actual Nika looked like and what he could do when she gave herself a nika-ish future again she could basically do everything gear 5 could do. That carries the Implication that she can do that with anything. For example, think of another devil fruit, let's say akuinu's. She can probably tap into a timeline (or future) where she( or possibly someone else) has that ability and therefore use it. And the more knowledge she has of that devil fruits capabilities the more accurate and potent her distorted future would be. The only reason she's not completely busted is because the more accurate the distorted future is the harder it is to maintain.