Lots of people will say 303 Aerospace Protectant. And that does look good. Consensus I've seen is to apply it monthly. I'm probably going to use this on my bumpers and mirrors. Maybe on the interior also. Might even hit the tires with it from time to time including the spare tire.
I'm planning to give Adams Graphene Spray a shot on the top though which is supposed to offer 6-8 months of protection. Seems like it might work pretty well.
I haven't even gotten my Jeep yet so can't really comment on any true results. But it's something I spent some time looking into and is a concern for me also.
I think 303 is probably going to be a popular answer and that could easily be used on top as well as all other plastic.