Fusion does have some issues. It can be a bit buggy, and I have fights with it sometimes when I’m laying out a sketch. The way it sketches reference other elements is a little tricky. Then again, I prefer Creo, which (I feel) handles external references much more gracefully.
Sketchup makes me shudder though. I’m sure the modern version is better than when I messed around with it, but I really don’t like the interface myself. Each to their own.
Anyways, onto the code!
So some interesting things are happening here. Your Z origin appears to be the bottom of the material rather than the top. With this, the Maslow will try to cut the air 3/4" above the work-surface, stepping down as it should until it just touches. I took your Z-heights and laid them out in this table to illustrate the point:
The original column is exactly what’s in your code. The difference tells us what the step-down is for each pass. The corrected column is what those heights should be. The really weird thing (to me) is that it has a pass at the stock top, which would just barely kiss the surface. That pass doesn’t help the cut and just takes extra time.
Based on what I’m seeing from the code, it looks like you set this point as your origin:
The other thing I noticed is that your feed rates are set way beyond the Maslow’s max speed. It doesn’t matter too much, because the firmware will throttle back to it’s own maximums and it should still cut alright. That will mess up your own planned feeds and speeds, though, because it can’t lower the RPM proportionally to the feedrate. This could cause rubbing, which will dull your tool and, in extreme cases, create a risk of fire. That would only happen though if your feed and speed were wildly different than what they should be, though.
Do you mind sharing your Fusion 360 file? I can run you through the process of setting up your toolpaths.