Styling/symbolizing (rule-based option) a roads vector layer with intersections of streets with different styles I have incorrect (and annoying) overlaps of the different symbolization styles. is it possible fix the problem?
You need to set the symbol level of the feature you want on top to a value higher than the other ones. This is true both vertically (road type) and horizontally (component of the road style for a given road type).
In your example, if you want the blue line on top, set the last line, layer1, to a value of 3.
It may also be necessary to hit
apply on the main styling window to see the changes.
As an example, the following symbol levels will draw the green area (0), then the blue area (1) and at last, on top of everything, the center line from the low line (3)