Good job getting across the finish line. I do think the flashcard market (particularly subscription) is pretty competitive so bear that in mind.

Without an export option (which I didn't see listed in the features), you're going to have to convince people that your walled garden is worth the price of admission.

Related, I used to have a dedicated flashcard study application that could handle "card variations" but it was a hassle since the app was desktop only. With a bit of JS and custom card types, you can actually do this in Anki now which gives the benefit of dedicated mobile app, syncing, etc.

https://ankiweb.net/shared/info/163606663

I experimented with autogenerating variations of a single card using LLMs but at the end of the day, the best flashcard is probably the one you write yourself. (similar to mnemonics)