Finally, I can easily select elements that were non-selectable-without-holding-cmd in the "design" mode. The thing that shows paddings and margins is a godsend, AND it stays put when you move your mouse somewhere else and switch to another window. The size tooltip also now shows the actual helpful size in pixels in addition to the unhelpful "hug/fill".
The choice of Jetpack Compose as the only Android code format is strange. Most people, even those who do embrace The Google Way™ of Android development and Kotlin itself, don't take it too seriously and don't consider it production-ready. It would be nice to have support for the good old XML layouts.