Ability to import brand specific fonts

I am looking to try and keep my NPS survey on brand as much as possible. Is there a way to import fonts into the theme or would I need to draft the NPS template outside of GS and import the whole thing? Currently there are only 4 fonts and a default in the drop down. I have had numerous end users question the NPS as SPAM or phishing emails as it does not represent the brand images/format they usually see.

The font options have been increased in Survey Themes. It will also include the fonts available in  Email Template designer. This change is being shipped with 21’Jan Release (Expected to hit production by end of Jan). At the moment, system doesn’t allow to import custom fonts. 

Hope this helps