Matching UI to designs was horrible on Android, at least as of ~1.5yrs ago. Even if designers were shooting for "Material". Plenty of rough edges. I wouldn't say 2x-3x longer for a typical project, though.

I could see there being issues with relatively new-to-Android developers not appreciating the degree to which advice from the official docs, especially relating to structuring applications, should be taken with a largish dose of salt, leading to slow-and-getting-slower development as an Android project went along.

It might take that long if you’re doing extensive UI theming and lots of custom widgets, but relatively few apps actually need those things. Even accounting for branding, a solid color scheme paired with Material Design on Android and UIKit on iOS are mode than good enough for the vast majority of cases. Creating garden variety CRUD apps with pleasant UX doesn’t actually take that long; it’s doing backflips and cartwheels with design that’s time consuming.

If you creating a hybrid app the apple app process takes longer (needs approval) and involves more resources (how much is an apple license these days last I checked it was 100 us)