But the Obsidian iOS app forces you to use the default iCloud location for your vault folder, which cannot easily be accessed by other apps even on Desktop due to the strange macOS/iOS permissions. For example, if memory serves, Chrome on desktop will not generate .webloc files there by dragging and dropping the URL from the address bar (although Safari will).

For my use case, I do not do much note creation while on mobile, so it's enough to use iOS Files app with a bunch of favorites.