@acribit and @theluthier I tried versions from 2.66 up to 3.2 and there doesn’t seem to be any difference in detail size (which makes sense, because this is measured in pixels).
What does make a difference (again, because it is measured in pixels!) is the size of your window and resolution (basically the size of your pixels)
Here I made the same stroke with the same brush and settings, but the top one was made with Blender in fullscreen and the lower one with blender in a small window:
