GetScrollPercent.tsx

import React, { useState } from 'react'

type ScrollProps = {
  layoutMeasurement: {
    height: number
  }
  contentOffset: {
    y: number
  }
  contentSize: {
    height: number
  }
}

export default function Component(){
 const scroll = ({
    contentSize,
    contentOffset,
    layoutMeasurement
  }: ScrollProps) => {      
    return ((layoutMeasurement.height + contentOffset.y) / contentSize.height) * 100 //return scroll in %
  }
return (
  <ScrollView onScroll={(event) => scroll(event.nativeEvent)} scrollEventThrottle={16}>  </ScrollView>
) 
}