It did not exactly sound that way. As the main buzzwords and keywords were either about native Mobile Apps (Android) or Angular/NodeJS or _javascript_ beside Progressive Web Apps.
_javascript_ in the browser (AJAX, also to some extent others like Angular) for Rich Web Clients does have support by specs mostly JSF.
There is nothing that prevents the use of Kotlin alongside Jakarta EE, although the original message was more about Kotlin on Android. It can also be used in Web or Microservice applications. Here an example for using Kotlin with Servlets:
https://kotlinlang.org/docs/tutorials/httpservlets.html
Using technologies like OpenDDR (the Open Source implementation of the W3C DDR Spec) for more responsive Mobile Web Applications is something, we did both for Java Servlets and Spring MVC. It is also possible with e.g. the Jakarta EE MVC spec, and I discussed the prospect with its contributors. They are still busy getting the Spec (JSR) Final, but if you (anybody on this thread) feel, this was a good use case for MVC, please get involved.
There are companies like Vaadin working with PWAs on the JVM already:
https://vaadin.com/pwa There shall be others and as Microsoft recently got even more Java (and Java EE) talent on board, I guess it's just a matter of time, before it will offer Jakarta EE based PWAs as well.