I would advice testing this idea on iOS only, find PMF, find SEO patterns, then consider expand. It also depends what framework you are using to build the app, cross platform vs native. It is not worth maintaining two platforms in the beginning, not just dev efforts, QA efforts, but just understanding how these two platform works would consume lot of your time.

This is not OP, but my experience with releasing apps on android is awful. It needs 20 testers who need to test the app for 14 days before it can be released to production. Its a major bottleneck for individual developers. Hope OP isn’t stuck with it.