Did you restart your phone and cleared system cache? Did you try going to apps, settings, finding google play store and google play services and clear the cache and data for both apps? Make sure you dont have any permissions denied as well. You can also unistall the updates first.
Did you try clicking on the notification and updating Google Play Services? Also, do you have Google Play Services moved to your SD Card? If so, moving it back over to your phone may help. Another suggestion I can give is to turn off developer options because I only turn it on when I need to do something that requires it and certain settings you may have on or off in there could affect you being able to download. I hope this helps.
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