Hi and thanks for reading
I sure it's possible to improve greatly the performance, especially since last year (the release of my article).
In addition, Cloud Run team has been improving the platform, and espcially for java runtime, partly thanks to this article.
By discussing with Googlers, Graal compilation isn't a real solution. Firstly, it's not yet stable and fully usable in production. Secondly, Graal compilation is Oracle product, and the future of the licencing is not clear.
Recently, I improved Spring Boot cold start performance thanks to APPCDS feature. I'm writing an article on this, co-authored with the Googler that help me on this.
If you also have tips on this topic, don't hesitate to share them!