If you're using uBlock, you can one-click block remote font loading from a domain in the badge popup menu (or write custom rules using the no-remote-fonts: or *$font syntax). This will force a fallback to system fonts, which should be perfectly fine.

This hardly the "best" solution, but, everyone has uBlock installed, and it's literally a 5-second hack.

With pictures: https://github.com/gorhill/uBlock/wiki/Per-site-switches#no-...