I would say that now is not a good time to participate in test nets or bounties with missions like token swapping or similar tasks. The fees are high at the moment, and most of the projects are scams. In my opinion, the best time to engage in a test net is during a downtrend when the fees are more acceptable, so even if they scam you, it's not as significant. Currently, the best way to make money from the start is to participate in bounties involving sharing, posting missions, or buying some cheap new meme coins.
Spending much fees for eligible airdrop some time is not worth, many retroactive airdrop change their rule few days after snaphoot after participants loss much money for purchasing fees without hold minimum required amount.
Better testnet without spending much fees and has potential when the project launching their mainnet to earn much airdrop reward allocation, have many way to earn in cryptocurrency not only airdrop but also participating in bounties and content events still worth although have many participants joining.
For airdrop make good research if spending much money or hold some coins for one or two months checking with potential profitable or get loss with more coins holding.