Logically, I'm not seeing "contradictions" in the size limits....

Dock widgets fall into one of 4 bars - top, bottom, left or right.

If any widget has a minimum dimension applicable to the bar "thickness" (height for top and bottom, width for left and right), that (plus frames) becomes the minimum dimension for the bar itself. If another widget in the bar has a maximum dimension less than the minimum dimension set by the other, the minimum wins and the widget with the maximum limit is drawn with some blank (background color) space around it, so it hasn't really violated its maximum limit.
Yes logically .
But the window layout( the one that positions the dock widgets ) tends to disagree.
Take the weird behavior you experienced as proof: sometimes you cannot move the dock widget(at least this happened to me), etc.
All I was saying: it will be pretty hard to get a "normal" dock widget behavior by imposing size restrictions - because you don't know how the user will resize a dock and where that dock will be dragged.

Along the bar "length" (width for top and bottom, height for left and right), no widget gets compressed smaller than its minimum, but the bar may be stretched longer than the sum of all maximums, either by minimum constraints on the opposing bar, or by the window itself getting stretched - in which case the dock widgets can be spaced out equally, preserving their maximum limits and again filling wigh background color.
Not sure if I get that. But if I get it, then I think its correct.

I only see contradictions coming in when the containing window is too small to accomodate all minimum sizes (in which case, shouldn't the window's size act to accomodate all contents?) If the containing window has a maximum size, I could see that precluding certain dock widget arrangements, but if the dock widget minimum sizes can be accomodated, then it should all work.
You could tweak the main window to expand size when the contents require it( and also in the limits of the screen ).

And of course, the separators allow adjustment within any available range.
Again, not sure how you will achieve that ( in the general case ).

Will be wonderful when it works.....
Yes, good luck on that, especially on "defeating" the main window layout.

Regards