There is a pending patch for this at
https://github.com/gwt-plugins/gwt-eclipse-plugin/pull/475. You should be able to pull and build this to get working again on the very latest Eclipse versions - and if you do, leave a comment, a code review, etc, and we can get this merged more expediently.
GWT is largely a volunteer project, the GWT Plugin for Eclipse doubly so - and while the GWT contributor pool is small, the GPE pool is more of a puddle. We're trying to raise interest in this among users and contributors, but we can't drag people to work on code or force them to pay for work to get done. The GPE tooling has never formally been part of the GWT project (first owned entirely by the App Engine team at Google if I'm not mistaken, then ran as its own github org for many years), but we're trying to bring these pieces in line as we grow.
Additionally, Eclipse marketshare isn't what it once was - I can't remember the last time I saw a project that ran better on Eclipse than IntelliJ. This is not intended as a slight towards anyone who is more productive with Eclipse, only as a remark that with fewer interest, it is hard to keep the project going.
Finally, the workaround is straightforward - 2023-09 was the latest as of 60 days ago, falling back to it will likely not destroy any development workflows.