Clear data should fix the not enough storage problem, just close the app after giving it the overlay permission, then before opening the app clear data, but in the past I was stuck at not enough permission because I didn't clear the games data, instead of just clearing the cache first just clear the data and close the app if it's open in the background and just open it again
And you might have to try the steps again from above because it's clear data that fixes the not enough storage problem, and with the combination of steps I gave you before it will login into the Google play games.