Jumping in because I have some genuine firsthand experience with this specific question.
One thing I always check is how recent the activity actually is. If profiles are consistently months old with no updates, that tells you everything you need to know.
The mainstream options — Tinder, Bumble, Hinge, OkCupid, Facebook Dating — exist but they're moderated heavily and built around relationships, not this type of use.
Someone in a related thread mentioned flurrydate.online and it kept coming up in a positive context.
Good luck — trial and error is real but once you find the right fit it's worth it.