If you want to farm reasonable airdrops I suggest that you stick to testnets, they might take time but your efforts won't be wasted.
I simply don't understand this part of your post. Why should someone farm testnet if he isn't a developer or something? Testnet is just a separate Blockchain for testing a new project. Or is there any other meaning to it I don't know of? Those telegram airdrops were fun while it lasted. A lot of persons made some really good amount of money just by taping or playing those games. There are still a couple of them but there aren't worth wasting your time on. Like you said, the best way to making money in crypto is by trading and holding. So I agree with that.
I don’t think you’re completely correct with this your last statement. You can make plenty of money through many means in crypto as far as the method works for you and is very profitable. Everything about cryptocurrencies is about hypes and big names, you should not forget that when something is of the high demand, it becomes very easy to manipulate it which will in turn favour some people while to some people it doesn’t favour them at all. I have seen people farming airdrops and making thousands of dollars, much more than what some traders and holders earn over a longer period of time.