As far as I can tell the only information I can see from purchases are the buyer's email address and IP address, and the transaction handler (i.e. paypal) and transaction ID

Depends.

Itch has 2 ways to sell.

The first is that you pay Itch directly, the information goes to Itch and it only delivers the basics, such as the email, the transaction ID. If at the time of purchasing, the seller is Itch, then you can rest assured.

The second way is that the game is hosted on Itch, but it is not sold by Itch, otherwise it is sold directly by the owner of the game. At the time of purchase, the seller's name should be different from Itch.

In that case, you are paying the seller directly