Hi, welcome here!
Some first ideas's for the 'not so smooth' outside:
-it's a direct drive extruder I suppose? Is it skipping while extruding (a clunck clunck clunck sound)? When so, adjust the tension of the pressure on the drive gear.
-did you measure your filament or just added the 1.75mm in the material setting? Measure the filament with a caliper in various directions, take the average and put that in the diameter in Material settings.
-set the extrusion width to 0.4mm (your nozzle diameter) . Layer height first to 0.2 or 0.25mm.
-Don't print to fast yet. As I don't know if your firmware is capable of acceleration, you have to find out yourself reasonable settings I think. Unaccelerated is 20mm/s(perimeter and 40 (infill) ok, but accelerated 60 and 100mm/s for example. As you have a CNC machine I suppose it's not build to speed, but more to have a solid (so heavy) XYZ movement, resulting in lower speeds then for a 3D printer I suppose, but I can be wrong.
-print a simple calibration box (2 loops, 100% infill, so solid) (stl attached) first with that setting and see what the result is. To much is pushing the filament out (and probably also a skipping extruder) to less gives a poor layer bounding.
Just after done the above it make sense to adjust some more settings.
about the ears of the owl: I think you haven't set the destringing values ok yet:
- on the style tab: check: loops form insite to perimeter, wipe, destring
- on the material tab maybe start with a jump and trigger of 5mm. a wipe of 5mm and prime and suck 0.5mm. It's very dependent of the used hardware/extruder so you could end with higher or lower numbers (print two calibration boxes at one time, so you can see the effect of adjusting of destringing.
-when you use LinuxCNC I have read that there were some issues with destringing because of the settings of Linuxcnc, resulting in a very poor print. (I'm not sure but it had something with G0 commands to do).
-set the flow tweak to 1. For PLA a slow print can be done at 200 degrees celcius, but I print faster and set it at 220grC.
At the printer/hardware tab the Loop/infill overlap setting is important. With me, at 20% there was a poor connection, at 100% there was to little room for the infill.
-Be sure your firmware isn't overruling the settings you make in Kisslicer (speed. temperature, destringing etc).
I hope this helps a little,
Bart