I kept getting the warning when trying to load preload a google font.
Turns out I was missing the fact that the font was being loaded as a style from google. I solved this by setting the as="style' and then using rel="stylesheet preload prefetch".
See code example below:
<link
as="style"
rel="stylesheet preload prefetch"
href="https://fonts.googleapis.com/css2?family=Roboto:wght@300;400;500&display=swap"
type="text/css"
crossorigin="anonymous" />
Happy coding =)