I have the same problem in a Samsung S9+ after an update of Android-Samsubg system. I fixed it loggin at Spotify through internet URL on Chrome and reset the password of my premium Spotify account. I log in again and was fixed.
Prevously I tried uninstalling and reinstalling Spotify, also shut up my cell phone, also loggin out and relogging my Googke account but anything work. The only think that works was log in through Spotify website and changing my password for a new one.
I had the same issue initially with Google Smart Lock. I've tried all the suggestions on this string and unfortunately, changing my password in Spotify doesn't resolve the issue. Neither does changing the password to match my google password, uninstalling and reinstalling Spotify, forgetting my password in the saved passwords on my phone, etc. I'm so frustrated that I've been paying for Premium yet haven't been able to use my account in almost two months.
One thing to note is that after I changed my password, the smart lock banner stopped showing up before it crashed, and now it just crashes with no banner 😞
Hopefully someone from Spotify can provide a solution that works.