Admob ads are not displayed as specified - react-native

Question

I have an app that is currently live in the store. After clicking a button 3 times in the application, an advertisement is shown. There has been a serious decrease in advertising revenues in the last two days. The reason for this was that on some devices, it was necessary to press more than 3 times for the ad to appear. On my friend's phone, normally it was necessary to click 3 times for the ad to appear, but now after 13 clicks, the ad appeared. How can I solve this issue?
Splash screen
import { View } from 'react-native'
import React, { useEffect } from 'react'
import mobileAds from 'react-native-google-mobile-ads';
export default Splash = ({ navigation }) => {
useEffect(() => {
mobileAds().initialize()
.then(e => {
navigation.navigate("MainScreen")
})
}, [])
return (
<View />
)
}
MainScreen:
import { Button } from 'react-native'
import React, { useState, useEffect } from 'react'
import { InterstitialAd, TestIds, AdEventType } from 'react-native-google-mobile-ads';
const adUnitId = __DEV__ ? TestIds.INTERSTITIAL : 'ca-app-pub-XXXX';
const interstitialAd = InterstitialAd.createForAdRequest(adUnitId);
export default MainScreen = ({ navigation }) => {
const [request, setRequest] = useState(0)
useEffect(() => {
interstitialAd.addAdEventsListener(({ type }) => {
if (type === AdEventType.LOADED) {
interstitialAd.show();
}
});
}, [])
useEffect(() => {
if (countOfRequests % 3 == 0) {
interstitialAd.load();
}
}, [request])
return (
<Button
title='press'
onPress={() => setRequest(prev => prev + 1)}
/>
)
}