For a simpler APK-based approach, you can use general Google Installers: The Open GApps Project
If you're looking for a Gapps installer for Android 9, here are some general steps: tta pie gapp installer for android 9 link
While built for Android 9 Pie, it is specifically effective for China-market devices or ROMs (like MIUI China) that lack the "Global" Google package. Understanding GApps for Android 9 For a simpler APK-based approach, you can use
Open the Play Store and sign in. You may need to manually grant "Full Permissions" to Google Play Services and the Play Store in your device's settings to ensure they work correctly. Alternative Methods For a simpler APK-based approach