OK so the scripts required for the customizer font controls is not loading due to an error. Which would generally be a plugin conflict. You can try disabling plugins to see which one is conflicting.
I would begin with the header footer plugin – there is actually no need for this. Instead:
Go to Appearance > Elements. Create a new Hook element.
Add your scripts in to the content, select the hook, in your current case it is the WP_Foot
On display rules tab set this to Entire Site.
Thanks David and Tom,
I found this advice on a website with tips for Generatepress, they gave the advice to add this snippet. Now I know what it is for. It’s properly not a snippet I need. It’s deactivated and fonts are working.