some scifi universe where they hand out anti aging perfect health pills like tic tacs. That would probably be a pretty interesting place to check out for some time. If it’s an innate ability to travel and I don’t have to worry about getting stuck in a universe, I’d probably want to check out some questions like “what if the Roman empire collapsed way earlier?” or “what if someone killed Hitler as a child?” or “what if religion didn’t have such an appeal to people?” (though I suspect I’d be going back to the first universe with the last question).