Installing a fresh manually resolves these issues.
Hold the power button and select . This allows the new Play Store to register correctly with Google Services. Google Play Store Apk For Android 8.1.0
Yes. Use a root file manager to copy the APK to /system/priv-app/Phonesky/ and set permissions to 644. Then reboot. The Ultimate Guide to Google Play Store APK for Android 8
If an app requires Android 9 or higher, the Play Store will block installation. You cannot bypass this by updating the Play Store alone. You would need to install a custom ROM or find an older APK version of that specific app. Google Play Store APK for Android 8