Maybe this can help. Basically you’re looking to split your screen into virtual screens.

Don’t know if this will work on the fly though.

That’s great to see! HappyCow is already a decent option, but something vegan oriented is of course better. Do you plan to also release your app on F-Droid or similar open source stores?

Cheers for the work!

I would mind. No single person should have that much wealth.

I have several grocery stores of different chains in my vicinity, in a 3km radius I could probably choose between 10+ locations (I just checked after posting: There are at least 18 grocery stores within that range and some options like farmer markets not listed). I only go to the closest ones (~500m) by foot, for most things further away I take my bike.