Some of the wallet has second option to login into your account, private key is one of those way to recover or re-login your account. You should keep your private key in a private and secured place where you are the one who can access this. If you backup your data into drive make sure this will not accessible in public and don't try to put the drive into affected computer to avoid stealing of information. If you save your private key in your accounts including google drive make sure you set up all of the settings of your account such as improving of the securities and don't login this account into other public places such as computer shop and other devices this might put you in a risk. Better to choose wallet with 2FA Authenticator, SMS verification, Email Verification, PIN and with notifier system for the tracking of your every transactions.