Unable to sync chrome passwords on Huawei P20: "Android system sync disabled"
Power saving mode is the problem. Go to Settings > Battery > turn Power saving mode off.

Then go back to Settings > Users &amp; Accounts > check Auto-sync data.

A few minutes later, everything will be synced.

(From https://techandcoolstuff.com/how-to-fix-auto-sync-data-greyed-out-huawei-mate-20-pro-user-accounts-not-synchronizing/)