From the help, to enable symbol levels I should tick "Enable symbol levels":
but there is none in my QGIS (3.20.2-Odense):
How do I enable it, I need to draw my red symbol on top of the green? I'm using rule based symbols.
QGIS 3 – Where to Enable Symbol Levels: A User Guide
qgis-3symbology
Related Solutions
In the table of contents panel where your stretched layer is showing, do a long click and hold on the text next to the colour ramp symbol this will allow you to edit that text.
I suggest to :
Duplicate the layer (Right click on it in the layer panel and duplicate)
Give a small size to the duplicated layer
Refresh in the print composer ( you will have two "Coniferous Tree" Layers)
Uncheck the "Auto Update button", select the Bigger layer and remove it from the legend
Best Answer
It is not possible to set Symbol Levels with Rule-based symbols. To have what you are looking for you must be in "categorized" mode.
Change rule set to categorized in symbology option: