it should be possible for egui to be built to run on mobiles too, if the UI has been changed to fit the dimensions... i was working with an IMGUI library called Gio back in 2018 that you could do that with (golang of course)

Not necessarily gonna pursue low-data usage at the cost of poor ux. It is more like taking advantage of knowing well how nostr works to not ship code that carelessly connect to more relays and asks more events than needed.

It might be harder than you think