Never use cardboard so cant really comment. I was able to easily cut through a piece with your lower power settings but like I say never use it so it’s a data point of one. As long as you entered the power and speed correctly and the material height correctly there isn’t a lot to screw up.
Looks like the cut edges were clean on the cardboard. The MDF doesn’t surprise me at all.
There should be setting that allows you to get through the thin oak just fine. Really won’t be able to tell much until you get the Proofgrade. It’s not that the PG is special, but it is a fixed piece of information that we can all compare.
The Glowforge has plenty of power to get through most 1/4" organic materials but plywood isn’t always the same, MDF isn’t the same, etc.
BTW: that’s some nasty looking MDF. Might try some thin birch plywood, or other thin hardwood from the hobby section of the big box store if your PG is a few days out.