I try to run .001-.002" per tooth and I often run ~15,000 RPM. Depth of cut and stepover are somewhat limited by the rigidity of the machine. I usually run 75% stepover, to avoid problems with full width cuts. A very good (expensive commercial grade) CAM would allow me to run the parameters I'd really like, but if I had the money I'd be running a Hass Minimill or similar instead of my frankenmill.
A slotting (full width) pass is always conventional, think about it.
In the video, the aluminum overheated, clogged the flutes, stopped cutting, and broke. With some lubricant it may have made the cut. Depends on the grade and hardness of aluminum and the cutter type.
Have you checked tool runout when installed in the spindle? Too much runout effectively makes your two flute a single flute and the feedrates will be wrong which kills the cutter. 0.5mm DOC at 400mm/min is about all I could do with my old spindle. Another issue is plunge feed rate, this used to kill me a long time ago. If you attempt to plunge at the full feed rate it will instantly clog the cutter in AL.
Did you define your stock properly in your CAM? Maybe it thought your stock was equal to the extents of the part, which means it thought it would be making a small radial cut and instead you had stock there the CAM didn't know about. This sounds like a logical explanation for what happened. Just because it reversed direction (+Y toward -Y) doesn't mean the cut would have been climb if the stock didn't exist there.
CAM is what limits the usefulness of CNC in the home shop. When I got into it I played with the free stuff out there and made a few parts with dxf->gcode programs that existed in 2006 or so. I quickly realized that if I wanted to make anything 3D I need a real CAM software that was going to cost 1000-4000USD. I ended up with VisualMill for 750USD or so. It works, and if you figure out it's quirks you can trick it into doing exactly what you want, but it doesn't do anything fancy. I added a 4axis and looked at CAM again this year. Anything that does continuous 4th starts at 4000USD.