Yes, you can do that. UniFFI allows you to generate Kotlin and Swift wrappers, which you can wrap in a RN wrapper. We did this at work for a cross-platform mobile app, it's a bit of a headache to create because that are some subtleties with async or these kind of things, and they are handled differently in the UniFFI wrappers and RN wrapper, but for relatively simple libs I find it pretty convenient.