FYI We just uploaded a new version of Android Studio with Declarative support provided by Google that fixes several issues that were showing in

settings.gradle.dcl

files. You can find it in the Google Drive linked here https://declarative.gradle.org/docs/getting-started/setup/#ide

Is there any reason EAPs or canaries from toolbox cannot include dcl support?

The Studio support is currently worked on on a feature branch because we break things too often in Gradle itself and the tooling librairies. If the support was shipped in the actual Studio product already then we would have to maintain some level of compatibility. IOW, this is to allow us all to move faster.