Hello,
Thank you for reaching us.
Yes, Roboto and Roboto Slab are the default fonts of Accelerate Free theme. If you want to change a font then the feature is only available in Accelerate Pro theme so if you need further assistance or are interested to learn more about this feature, please feel free to open live chat in our site https://themegrill.com/ and our team will assist you further there regarding this.
Also, for disabling the google fonts on your site, if you can code on your own then, you can achieve those via the child theme: https://themegrill.com/blog/tutorial-creating-wordpress-child-theme/ and utilize this function:
https://developer.www.ads-software.com/reference/functions/wp_dequeue_style/ of WordPress for same.
And, you can use the handle: accelerate_google_fonts to dequeue Google Fonts on your site.
Furthermore, you can also use the third-party plugin for removing the google fonts on your site. Here is the plugin link: https://www.ads-software.com/plugins/disable-remove-google-fonts/
Let me know of any confusion while you perform the action and I will be back.
Regards
