When #29159 is merged it will be possible to update the area of the selected Template Part:

Since we have dedicated icons for these areas that will be surfaced to users in the Toolbar, List View, and the Inspector, it may be worth exploring designs that incorporate them into this selection flow in order to establish holistic continuity in the UI.

One option might be to use a segmented control instead of a dropdown:

Another option would be to stick with the select but enrich the dropdown:

Whichever solution we go with, we should be aware that this element will likely exist in other environments, e.g. #29222.