I think Classic with Alpha Beta and Untamed is fair, with no new sets ever added. Those sets were before the game really blew up. Certainly you'd at least include Beta surely. I don't see why the prize allocation should be smaller either. If you invested $5k in 2019 you should earn the same per victory as if you invested $5k in 2023. Allowing otherwise is just asking for card values being almost guaranteed to gradually depreciate over time.