I was wondering if there was something I could change in the config file to allow grappling hooks from the grappling hook mod to be used in claims. I'm on 1.20.1 and when I try to use a hook in my claim it launches but then disappears before hitting a block.

You need to add the projectile entity of the grappling hook to entitiesAllowedToGrief in the main config file, where things like eggs, arrows, tridents are already included by default.

Also do the same for entitiesAllowedToGriefEntities if you want to allow the projectile to land on entities too.