Thank you veryyyy much. I am doing it solo and I am not a CS major. This comment made my day!

I just have one concern though, the user will be interacting heavily with the flashcards while studing and I want to store that info for the algo. Should i go with an on-device database for it? or Firestore can handle it?

Yeah. And firestore is real-time so you could do some cool stuff with that. Try their sdk out it’s really easy.