If you'll provide the report or the store URL, I might be a better help. However, I'm pretty sure Google fonts are taken from an external file, so it might be that you're extracting fonts to your code that you are not using. But from my experience, the impact on your speed in this case is insignificant.
In most cases, what helps to increase the website speed is optimizing images and removing unnecessary JS files.
@Cmas you can usually find fonts and 3rd party scripts in your theme.liquid file (in theme editor > Layouts).
Give that a good read, even if you don't fully understand the code, if you read it line by line you can probably pick up the 3rd party resources you don't need, and identify fonts.
Make sure you duplicate your live theme first, then work off the new theme and preview it after making edits, to make sure nothing gets screwed up on the live site in case you accidentally alter something that's needed.