Possibly unfair to point the finger at RN here, but we found that the amount and complexity of code involved in developing using RN + JS + Redux was much higher

Possibly unfair to point the finger at RN here, but we found that the amount and complexity of code involved in developing using RN + JS + Redux was much higher than when just using Swift (< 50%). We've yet to repeat the experiment with Android/Kotlin, but I'm confident we'll get similar results.