Well presented, however, a few flaws in the science.
I suggest researching “early apex” as that is the safest and usually fastest line selection outside of a purpose built racetrack as it delivers the exit closer to the inside of the turn, leaving more options.
Keep in mind that the apex is in the line, not the corner, so you move it where you need it. The confusing bit comes from multi apex terminology- a double apex turn can often only have a single apex in the line, but it sums the situation best so that is the term.
And just to point an obvious piece of the gilbert vid, the motorcycle was actually on the correct line, at the apex, when you stopped motion.
Source: former motorcycle roadracer, car racer, shifter cart racer, cyclist.
Again, well presented! (but follow up with one explaining late apex)