yeah, unfortunately, a lot of airdrops seem to be not trustworthy, but there are definitely better projects with airdrops AND bounty campaigns, so you can't do anything wrong with them.
For example DeepOnion: I follow this coin for a couple of months now and participate in their airdrops as well as their bounties.
Their dev team does a really good job: recently they announced an Android Wallet for example. I'm mobile all the time so that's a big plus

Always do your own research of course, but you can start here: https://deeponion.org/community/ , read their White Paper https://deeponion.org/White-Paper.pdf