Eclipse 2023-09, Java 17 and xhtml content assist not working

Question

I am running Eclipse 2023-09 (4.29.0), Java 17 (Amazon Corretto 17.0.8_8) and have noticed that content assist we had available when using Java 11 on our xhtml pages no longer seems to be working.

We have upgraded our webapp from JSF 2 to JSF 4:

    <dependency>
        <groupId>org.glassfish</groupId>
        <artifactId>jakarta.faces</artifactId>
        <version>4.0.1</version>
    </dependency>
    

And we also use primefaces version 12:

    <dependency>
        <groupId>org.primefaces</groupId>
        <artifactId>primefaces</artifactId>
        <version>12.0.0</version>
        <classifier>jakarta</classifier>
    </dependency>

We've updated the namespaces in our xhtml pages from URLs to URNs like the following:

xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="jakarta.faces.facelets"
xmlns:h="jakarta.faces.html"
xmlns:f="jakarta.faces.core"
xmlns:p="http://primefaces.org/ui">

And I've double checked under Eclipse/Preferences/Web/Html Files/Editor/Content Assist everything is checked.

My project within eclipse is marked as a maven project, I can see the Maven Dependencies directory listing all the jars, including both the jakarta.faces and primefaces jars, so the taglibs should be on the classpath and visible by eclipse, but still no content assist.

I'm guessing it has something to do with the javax -> jakarta change when we upgraded from Java 11 to Java 17 and maybe it's a bug in Eclipse? Either that or the tag libs are stored in a different place/location within the jar files and Eclipse doesn't see them correctly?

If anyone has any ideas (or if this is a known bug) I'd really appreciate any feedback. Thanks for your time.