> As a general remark, I get confused and maybe even a little irritated when people conflate Android & iOS with macOS/linux/windows.
Android and iOS represent the majority of devices your software can be run on. They are ubiquitous, and also very dependent on a native UI frameworks that are a somewhat better developer experience than their desktop counterparts, but only because the years of accumulated cruft are less. Incidentally, Android actually does have a desktop mode for it's GUI. That said, users rarely use the desktop Android GUI.
> You can sort of kind of pull this off with a relatively limited web app
I've had better luck with electron and PWAs on the desktop than non-native mobile tooling. This is largely because non-native mobile frameworks often don't have access to the same libraries - or the abstraction layer loses fidelity in trying to be cross platform. There's really no QT grade multiplatform tooling on mobile. There's some promising starts.
> I think it's extremely hard to design the GUI in a way that can work on both mobile and desktop platforms
It's hard to get a decent GUI on both Android and iOS that doesn't have a lot of rough edges with cross platform frameworks. They are coming along, but it's still just not quite there yet.
Android and iOS represent the majority of devices your software can be run on. They are ubiquitous, and also very dependent on a native UI frameworks that are a somewhat better developer experience than their desktop counterparts, but only because the years of accumulated cruft are less. Incidentally, Android actually does have a desktop mode for it's GUI. That said, users rarely use the desktop Android GUI.
> You can sort of kind of pull this off with a relatively limited web app
I've had better luck with electron and PWAs on the desktop than non-native mobile tooling. This is largely because non-native mobile frameworks often don't have access to the same libraries - or the abstraction layer loses fidelity in trying to be cross platform. There's really no QT grade multiplatform tooling on mobile. There's some promising starts.
> I think it's extremely hard to design the GUI in a way that can work on both mobile and desktop platforms
It's hard to get a decent GUI on both Android and iOS that doesn't have a lot of rough edges with cross platform frameworks. They are coming along, but it's still just not quite there yet.