I've been using the iOS RN app for years (on a phone that's currently 4 years old) and never had any performance issues. There may just be some transition pains they need to work through on Android
It's worth noting that even a cheap, used 3-year-old iPhone 11 [0] is faster in benchmarks than a new flagship Samsung S22 Ultra [1], and the disparity is much larger when comparing flagships of the same generation head-to-head. This is no excuse for slow software, but it does go some way towards explaining the speed of the iOS app.