6. Check their whitepaper and the team it's plagiarized/stolen or not (using plagiarism tool and reverse image), if you found it plagiarized/stolen... it's a red flags from their project and you should not join the bounty.
7. You can follow the recommended safe bounty of both this thread Safe Campaigns in the Altcoin section to join. Dont waste your time with others and list of bounties good quality (new update 23_06_2020). This is just recommendation and not force you to join, you can choose bounty whatever you want.