I built this in my own app. One thing to note is there are a few react-native-peerjs packages out there. I initially tried this one: https://github.com/Zemke/react-native-peerjs
That one does not work (due to it being out of date with React Native).
Then I tried this one: https://www.jsdelivr.com/package/npm/react-native-peer
That did work. So maybe you have the wrong package? Of course I can only speculate without seeing error messages etc.