Hi
We are unable to change the font name (we can't find it), please check the screenshot. Font name was missing there. Changing the font size does not work also.
Screenshots are not attached, please check
Please make sure that the following file is not empty and has the "fonts" element with the list of available fonts
design/themes/THEME/styles/schema.json
That file is untouched. It looks same as your screenshot. Sending a screenshot from my end. please check.
It is required to examine issue on your server. Please contact support team