Glad to see this is becoming a reality!
Quick Capture. As I stated here back in Jul 2023 (an many others are mentioning now), I think a crucial feature is ability to Quick Capture like Tana: Native Apps (Apple, Android, etc.) - #25 by Illusory. If Fibery Mobile app is simply a web-app tailored for mobile, I imagine Fibery’s current Quick Add feature will be accessible, so that should work fine, assuming the UI is tweaked.
Offline mode. I agree with other users here. In my experience, Fibery has issues loading content if connection is not highly stable (e.g. mobile data).
Search, view, edit. Probably goes without saying but I’d definitely still want to have the ability to search for entities, update fields and update rich text (with formatting options). Also, changing filters and sorting views should be available, since it is even more important on mobile (due to lack of real estate).
Nice-to-have, but not a priority:
Create new views. I could live with having to create views on the web since it’s related to “space configuration”, but if it’s possible that would be nice.
Push notifications. Would be nice to have dedicated notifications for Fibery on iOS.