React Nativeで広告ライブラリadmobのビルドに失敗する

Question

前提・実現したいこと

React Nativeでスマートフォンアプリ開発を行なっております。
広告ライブラリのreact-native-admob-native-adsで広告を表示させる機能を実装中です。
react-native-admob-native-adsの設定をAndroidの設定手順に沿って実施しました。
設定後、npx react-native run-androidでAndroidアプリを起動すると、以下のビルドエラーが出ており、解決ができません。

発生している問題・エラーメッセージ

FAILURE: Build completed with 2 failures.

1: Task failed with an exception.
-----------
* Where:
Build file '/Users/xxx.yyy/project/react-native-tutorial/node_modules/react-native-admob-native-ads/android/build.gradle' line: 31

* What went wrong:
A problem occurred evaluating project ':react-native-admob-native-ads'.
> Plugin with id 'maven' not found.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
==============================================================================

2: Task failed with an exception.
-----------
* What went wrong:
A problem occurred configuring project ':react-native-admob-native-ads'.
> com.android.builder.errors.EvalIssueException: compileSdkVersion is not specified. Please add it to build.gradle

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
==============================================================================

* Get more help at https://help.gradle.org

BUILD FAILED in 7s

    at makeError (/Users/xxx.yyy/project/react-native-tutorial/node_modules/execa/index.js:174:9)
    at /Users/xxx.yyy/project/react-native-tutorial/node_modules/execa/index.js:278:16
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
    at async runOnAllDevices (/Users/txxx.yyy/project/react-native-tutorial/node_modules/@react-native-community/cli-platform-android/build/commands/runAndroid/runOnAllDevices.js:109:5)
    at async Command.handleAction (/Users/xxx.yyy/project/react-native-tutorial/node_modules/@react-native-community/cli/build/index.js:192:9)

該当のソースコード

androidフォルダ配下のandroid/build.gradleは以下です。

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    ext {
        buildToolsVersion = "30.0.2"
        minSdkVersion = 21
        compileSdkVersion = 30
        targetSdkVersion = 30
        ndkVersion = "21.4.7075529"
    }
    repositories {
        google()
        mavenCentral()
    }
    dependencies {
        classpath("com.android.tools.build:gradle:4.2.2")
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        maven {
            // All of React Native (JS, Obj-C sources, Android binaries) is installed from npm
            url("$rootDir/../node_modules/react-native/android")
        }
        maven {
            // Android JSC is installed from npm
            url("$rootDir/../node_modules/jsc-android/dist")
        }
        mavenCentral {
            // We don't want to fetch react-native from Maven Central as there are
            // older versions over there.
            content {
                excludeGroup "com.facebook.react"
            }
        }
        google()
        mavenCentral() // ☆追加
        maven { url 'https://www.jitpack.io' }
        jcenter() {
            content {
                includeModule("com.yqritc", "android-scalablevideoview")
            }
        }
    }
}

appフォルダ配下のbuild.gradleは以下です。

apply plugin: "com.android.application"

import com.android.build.OutputFile

project.ext.react = [
    enableHermes: false,  // clean and rebuild if changing
]

apply from: "../../node_modules/react-native/react.gradle"

def enableSeparateBuildPerCPUArchitecture = false

def enableProguardInReleaseBuilds = false

def jscFlavor = 'org.webkit:android-jsc:+'

def enableHermes = project.ext.react.get("enableHermes", false);

def nativeArchitectures = project.getProperties().get("reactNativeDebugArchitectures")

android {
    ndkVersion rootProject.ext.ndkVersion

    compileSdkVersion rootProject.ext.compileSdkVersion

    defaultConfig {
        applicationId "com.awesomeproject"
        minSdkVersion rootProject.ext.minSdkVersion
        targetSdkVersion rootProject.ext.targetSdkVersion
        versionCode 1
        versionName "1.0"
    }
    splits {
        abi {
            reset()
            enable enableSeparateBuildPerCPUArchitecture
            universalApk false  // If true, also generate a universal APK
            include "armeabi-v7a", "x86", "arm64-v8a", "x86_64"
        }
    }
    signingConfigs {
        debug {
            storeFile file('debug.keystore')
            storePassword 'android'
            keyAlias 'androiddebugkey'
            keyPassword 'android'
        }
    }
    buildTypes {
        debug {
            signingConfig signingConfigs.debug
            if (nativeArchitectures) {
                ndk {
                    abiFilters nativeArchitectures.split(',')
                }
            }
        }
        release {
            // Caution! In production, you need to generate your own keystore file.
            // see https://reactnative.dev/docs/signed-apk-android.
            signingConfig signingConfigs.debug
            minifyEnabled enableProguardInReleaseBuilds
            proguardFiles getDefaultProguardFile("proguard-android.txt"), "proguard-rules.pro"
        }
    }

    // applicationVariants are e.g. debug, release
    applicationVariants.all { variant ->
        variant.outputs.each { output ->
            // For each separate APK per architecture, set a unique version code as described here:
            // https://developer.android.com/studio/build/configure-apk-splits.html
            // Example: versionCode 1 will generate 1001 for armeabi-v7a, 1002 for x86, etc.
            def versionCodes = ["armeabi-v7a": 1, "x86": 2, "arm64-v8a": 3, "x86_64": 4]
            def abi = output.getFilter(OutputFile.ABI)
            if (abi != null) {  // null for the universal-debug, universal-release variants
                output.versionCodeOverride =
                        defaultConfig.versionCode * 1000 + versionCodes.get(abi)
            }

        }
    }
}

dependencies {
    implementation fileTree(dir: "libs", include: ["*.jar"])
    //noinspection GradleDynamicVersion
    implementation "com.facebook.react:react-native:+"  // From node_modules

    implementation "androidx.swiperefreshlayout:swiperefreshlayout:1.0.0"

    implementation 'com.google.android.gms:play-services-ads:20.5.0'

    debugImplementation("com.facebook.flipper:flipper:${FLIPPER_VERSION}") {
        exclude group:'com.facebook.fbjni'
    }

    debugImplementation("com.facebook.flipper:flipper-network-plugin:${FLIPPER_VERSION}") {
        exclude group:'com.facebook.flipper'
        exclude group:'com.squareup.okhttp3', module:'okhttp'
    }

    debugImplementation("com.facebook.flipper:flipper-fresco-plugin:${FLIPPER_VERSION}") {
        exclude group:'com.facebook.flipper'
    }

    if (enableHermes) {
        def hermesPath = "../../node_modules/hermes-engine/android/";
        debugImplementation files(hermesPath + "hermes-debug.aar")
        releaseImplementation files(hermesPath + "hermes-release.aar")
    } else {
        implementation jscFlavor
    }
}

// Run this once to be able to run the application with BUCK
// puts all compile dependencies into folder libs for BUCK to use
task copyDownloadableDepsToLibs(type: Copy) {
    from configurations.implementation
    into 'libs'
}

apply from: file("../../node_modules/@react-native-community/cli-platform-android/native_modules.gradle"); applyNativeModulesAppBuildGradle(project)

AndroidManifest.xmlは以下です。

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
  package="com.awesomeproject">

    <uses-permission android:name="android.permission.INTERNET" />

    <application
      android:name=".MainApplication"
      android:label="@string/app_name"
      android:icon="@mipmap/ic_launcher"
      android:roundIcon="@mipmap/ic_launcher_round"
      android:allowBackup="false"
      android:theme="@style/AppTheme">
        <meta-data
          android:name="com.google.android.gms.ads.APPLICATION_ID" // ☆追加
          android:value="ca-app-pub-xxxxxxxxx-yyyyyyyyy"/> // ☆追加

      <activity
        android:name=".MainActivity"
        android:label="@string/app_name"
        android:configChanges="keyboard|keyboardHidden|orientation|screenSize|uiMode"
        android:launchMode="singleTask"
        android:screenOrientation="portrait"
        android:windowSoftInputMode="adjustResize">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
      </activity>
    </application>
</manifest>

試したこと

• compileSdkVersion is not specified. Please add it to build.gradleのエラーが出ていたので、gradleファイルにcompileSdkVersionが定義されているかを確認しました。上記のソースにある通り定義されていました。
• ネットで検索しましたが、有益な解決方法がありませんでした。

補足情報（FW/ツールのバージョンなど）

• "react-native-admob-native-ads": "^0.5.0"
• "react-native": "0.67.2"