Also, if you are looking for an open-source alternative, this may be for you
https://github.com/Jessecar96/SteamDesktopAuthenticator.
Haven't used it but the setup instructions look fairly straight forward. Not sure why you're not using the email only authentication. Having an authenticator generate codes on the desktop is kind of pointless if you are not constantly logging into other devices. If your desktop is compromised and data is revealed, the authenticator is likely compromised as well in that case. The entire premise behind mobile authentication is to have something physically separated generate an authentication code or token.
The e-mail authentication by default only asks you to enter codes when you are connecting from a non-authorized device or browser. Combining that with strong passwords for both Steam and your e-mail account and you're pretty much safe in 99% of situations.