That is rough. I assume this is a web application?
I went through a previous thought experiment about what would happen when we moved a paid up front feature behind a subscription. This was the outcome I came to. Unless the user bought and installed a physical app, on the desktop, outside of an app store, they were going to get the rug pulled out from under them.
No, its the stronglifts app. But I switched to hevy and I'm happy with it. But I did paper for a while and liked it until I missed mu graphs