I can see two issuesŞ
- a bit of overextrusion, followed by
- a bit of underextrusion,
perhaps just before retracting to change the layer.
The former will be improved by reducing speed (though I think you already print at pretty low speed) and/or reducing acceleration.
For the later, you may try "External perimeters first", though this might induce other artifacts. If you keep the default (unchecked) then reducing the retraction length/speed may help.