Unless you do your own tuning (or are willing to light money on fire) it’s hard to A/B test ski waxing/edge tuning. I kinda suspect this alleged olympic tuner didn’t cross compare, or just doesn’t ski in ways where you’d notice (he might just like skid turns through packed powder). Or he just uses backcountry noodles on groomed snow, and can’t tell since he’s using skis that won’t let him.
Going from dull edges (even “well maintained” ones) to freshly sharpened is quite noticeable on icy days. I use 0°/4° and like the responsiveness and grip.
From my long past race days (when I had to maintain several pairs simultaneously), I could tell that the wax design temp mattered deeply, though mostly >25f vs lower temp. High temp waxes are down right sticky in cold snow (and vice versa). But cold waxes are largely fine for middle temps (~10-20f or whatever). The (horrifying) fluoro stuff was also very effective, though probably banned by now if anyone is sane. I wasn’t able to tell the difference beyond the temp though, unless the skis were damaged. Though, I mostly just don’t wax these days since I’m not trying to eek out extra speed.
Base bevel (the angle trimmed off the metal edge from the side that sits on the snow) matters and is largely ignored by skiers/snowboarders, since tuners are cautious, and skiers don’t know to ask. It determines how responsive the skis are (going from 0° to 1° means you need to tilt your leg an extra degree). You can only decrease it (or clean it up) by flattening the entire base and then sharpening, which requires specialized equipment.
Edge bevel matters, but allegedly has diminishing returns. It (allegedly) gives a bit of extra grippyness. I’ve never quite understood why it matters, since it seems like it just narrows the metal very slightly. From my A/B testing, the freshness of the sharpening seems to matter more than the edge angle, but I’ve also never set it below 2°.