As a massive Crawdaunt stan I feel the urge to give you my two coins on this. As stan I mean that I love the 'mon, not that I think it's more viable than what it actually is, which isn't a lot. Anyway, I honesly believe that - outside of Trick Room - you are getting the biggest mileage out of Crawdaunt when equipped with a Choice Band (Crunch or Close Combat in the last slot) + Future Sight support. Aqua Jet is usually very weak but Crawdaunt's is strong enough to give it some late game potential and defensive utility alongside its Psychic immunity. Realistically, you're not sweeping with it simply because you won't safely set up with it as you said. Future Sight + Crawdaunt clicking Knock Off/Crunch is still damn near impossible for stall to switch into + you get your one hit against the more common builds, except it is more powerful and without recoil, before switching out. Heck, even though Adamant is 100% more Alpha, Jolly isn't terrible either because it outruns some key mon like slow Rotom-W, SpDef Lando-T, SpDef Heatran, Modest Magnezone and stuff.Crawdaunt is a great mon running through fat and I love it for that on some particular teams; that said, it only becomes more of a genuine threat the fatter your own team gets. Daunt having the bulk of wet toilet paper and the speed of a snail with a broken leg makes it difficult to set up vs any team that can play offensively and virtually impossible to utilise long term vs such teams. Fantastic at dismantling defensive cores pretty indiscriminately sure but vs any opponent with half-decent risk/reward assessment it's way too hit or miss to consider on a lot of teams compared to the available lures, trappers, and generally overwhelming offensive cores which have much more focused targeting in what they can remove or force chip on that makes game plans go a lot smoother. If you're having difficulty dealing with Crawdaunt then likely: you're playing your team too passively and giving it way too many opportunities to make progress since it's not a mon that's best handled defensively, your risk/reward assessment needs some polishing, or you're running generic stall (in which case you need to accept that you're playing the matchup fish game already).
So yeah, if you haven't tried it, I suggest you give Choice Band Crawdaunt a shot in a pivot-heavy, Future Sight offense/bulky offense - or Trick Room.
disclaimer: I know I used "you" a lot, but the only the first one is actually directed at you Tapeworm, otherwise it's for everyone reading