Cloudflare has been offering SSH CA-based authentication for more than 2 years [1], I wrote a guide back in feb '23 [2]. The announcement is more about offering new features, such as more granular user control.

[1]:https://web.archive.org/web/20210418143636/https://developer...

[2]: https://mdleom.com/blog/2023/02/13/ssh-certificate-cloudflar...