This starts out well outlining the problem then ends abruptly with "use this magical third party service to make your problems disappear" with no insight into how it's solving the problem.
It isn't providing another third-party service - just wrapping some JS around Google fonts d/l. If this is something you don't prefer, self-hosting font files with font-display property is the only way out.
Also, this isn't as performant as correctly self-hosting font files (because of separate DNS lookup to google font domain involved).
Also, this isn't as performant as correctly self-hosting font files (because of separate DNS lookup to google font domain involved).