I know you can visit some theme parks at certain times of year to avoid many children, however what I mean are theme parks built more for imaginative and fun-loving adults.
Take some of the park rides you might find in family theme parks that appeal to both adults and children, but instead of avoiding elements that may confuse/frighten children, they’re allowed to get more detailed or whatever may be more fun for people. Fwiw I’m aware of some smaller scale themed venues (particularly some horror-related ones), but I feel like I’m blanking on any obvious larger scale ones.
Universal does Halloween horror nights that is very adult oriented. It’s in their normal park but they are open a standalone Halloween themed park in las Vegas soon that will be similar but full time.
Busch Gardens too. It’s pretty fun, we’ve gone a couple times and had a blast.
Worlds of Fun here in KC does this too. Kids can enter, but the do not recommend they stay after dark. They have a parade, have entire areas that are outdoor haunted houses, and send people running through the crowd to scare them. It is a lot of fun. Most of these regional parks are all owned by the same company (Six Flags, IIRC).