Good morning,
Your first picture has the potential for some extra improvements 
.
Picture 2, the shot without nozzle, - this fire spot is half as big as on your square. If you have the standard nozzle, with the lens in the small reset and you remove it, then your test shot result may not be smaller, it is not logical. The spot is less as in picture 1 and only half from your square - with lens(?)
What are your settings for your test shots?
I would like to see some pictures with different power settings of your M1, from āalmost nothingā to a clear fire spot.
I would also like to see a picture with the result of a ramp test and a square 100x100 mm on cardboard or paper with 200mm/s and 17% power (engraved with proper focus).
Do you have other materials that you can test with? (wood or MDF, poplar plywoodā¦)
6.35 mm ā¦ I have some plywood that is exterior glued and which I have given up to use for most tasks. The result is not clean and neat and it takes too long to cut.
From 3-4 mm up, I use when I have to use exterior glued material, somewhat the same settings like you, max power (55-60%) and approx. 10mm/sec. And the result is, as I said, not pretty, with many not cut spots.
If you have the exterior-glued material and a laser beam that is not optimal, then we are a little closer to an explanation.
But letās do the last tests before the conclusion.