For anyone wondering, Robux-based subscriptions are entirely possible with developer products, similar to how games “ban” players with datastores and using the :Kick API.
I’m surprised there isn’t a popular package already out there for this, but all you need is to log the date with a DataStore when a user purchases a dev product and give them their rewards for a certain duration.
Currency subscriptions are a bonus that Roblox have added, and I see no reason to complain on a feature that is just there for those that want it.