I haven’t received any donations, but I don’t see how you can get scammed by that. For itch.io, there are two options you can do for payout.
If you’re worried about itch.io taking your donations, I don’t think they will. Although if you don’t withdraw your money, they may start charging maintenance fees depending on how much money there.
Itch.io actually uses the open revenue sharing model where you choose what percentage of your revenue goes to itch.io (0%-100%).
What specific concerns did you have with donation scamming?