Your thread title is a little misleading. KiCAD CAN create a board outline specified to a greater precision than any manufacturer can deliver, as long as the outline is fairly simple. You simply specify the location of every line segment in the outline - a tolerably tedious process for rectilinear outlines with no more than, say, a few dozen segments. Same thing for parts placement - edit the component’s “Properties”, all the way down to nanometers if you’re that picky.
As a practical matter, when a board outline becomes much more complicated than a basic rectangle, I create it in the stand-alone drafting program “LibreCAD” and import the result to KiCAD as a *.DXF file.
When it comes to creating a classic drawing showing dimension values, etc, KiCAD can add the arrows, leader lines, numeric values, etc . . . . but . . . . they aren’t attached to any particular object.
The above image is a reasonably well-done drafting project, if I do say so myself. But even though each of the dimension call-outs is visually associated with some feature in the displayed image, in fact they are independent objects that just happen to be floating in space near a particular line, vertex, center point, etc. For all of the software sophistication and digital advances that have gone into KiCAD, when it comes to adding dimensions and notes I might as well be working with a T-square and drawing triangles on a hard-maple drafting table, like my father did over 80 years ago.
Do I wish KiCAD was more capable in this area? You bet! Is it likely to happen any time soon? Don’t bet on it! In fact, this whole style of presenting information seems to be fading away, perhaps analogous to the demise of beautiful calligraphy documents produced in monastic communities before the advent of printing presses. I have learned to look at such a document and take in both its broad scope and specific details by visually scanning it. My co-workers - at least, those who have the time to be bothered by drawings at all - would rather open the drawing on a display screen and clicky-clicky to get information about some item or feature that is relevant to the moment.