Yes, ARB and Optimism provide airdrops that make their users happy with what they have tried to carry out the tasks given in each phase, I am also still hunting for airdrops to this day, and indeed there are lots of scam projects, if we are not good at finding potential projects it is very risky.
Moreover, nowadays airdrops need capital to participate in their airdrop events, so you have to be more careful in choosing projects.
BTW, did you take part in the airdrop event offered by the zkSync network developer? lots of people speculated that this event had crazier prizes, because there weren't that many who took part in this event.
For ARB and Optimism looks can't categories as airdrop project because we have spent our fees transaction active on their platform get qualify for earn both coins. But most profitable for participants earn airdrop from both coins with higher amount actually and right now seems difficult to earn airdrop with the same way like ARB and Optimism coins. Right now have been popular with zkSync network and we need spent much or higher fees each time transaction in this platform. Actually zkSync network still not confirm yet they will launch and have allocation their coins for airdrop participants. For retroactive its not guarantee earn airdrop but have getting risk for spent fees transaction and waiting one or two years later they will announce has airdrop distribution or not.