The biggest money making slot in crypto space is to be
1. a developer
2. build crypto wallets for new projects
3. find bugs in the system of many new projects
yes some paid for security breaching and all that stuff, rendering professional services is the best way to make money in crypto space now
See the difference between all you have mentioned with bounty and airdrop is that this 3 above requires certain skills for anyone to be able to use them to earn but bounty do not require any skills at all, as long as you can read and understand and write, all you need is an understanding of situation, if you are part of signature campaign, you need to know how to read and understand to be able to contribute and if you are a social media campaign, you even far less.