Yes, I’m that Normie-Pleb that has been annoying Wendell for a few years with the bugs I encounter.
For M.2-to-U.2 the combination Wendell is showing off in that video seems to be reliable:
Generally yes, the shorter the cables are the better but on the other hand cables shorter than 50 cm are less common and might be manufactured in more “flexible” factories that could need better quality control.