We may use any kind of font – Google Fonts, Adobe Fonts etc, as long as it is converted into base64 code within CSS.
For Google Fonts, please use this service:
https://amio.github.io/embedded-google-fonts/
For any other font, please use this service:
https://newbedev.com/converting-and-rendering-web-fonts-to-base64-keep-original-look
It is highly discouraged to load anything within the header or through @include method.
Final output should be something like this:
