I wonder if there is any way to fetch wether Steam Guard is enabled or not through the Steam API. I am using the openid library for my website but I can't find any variable that stores the steam guard status.
If you don't have access to the sdk (you're not in a software/game developer situation), then you can't tell how an account is secure if you're perfoming the task through the web api (for your website for example) The reason of that is to prevent people to get scammed by fake traders who search for weak accounts.
But if you want to make an api that use the steam api library, then the function you're looking for is ISteamUser which can acces the boolean BIsPhoneIdentifying that will tells you if the user have steamguard phone api associated to his account.
Check more about it and how to use the constructor here Steamworks API Reference > ISteamUser