Not sure what you mean. He had been working for 15km himself (with a few others), while McNulty, Martin etc, were doing no work at all in the first group, and still Evenepoel was one of the strongest on the steepest part of the climb.Sevilla is reasonably close in build and he was an okay TT rider way back in the day. And he probably lost over 4.5 s/km on the non-climb part of the ITT.
With such power advantage (I do not believe that it's only aerodynamics) it's a mystery to me why Evenepoel isn't a better climber relatively.
But it's not just aero, obviously, no. His wattages have been posted in this topic, and he weighs over 4kg less than January last year (below 60kg now according to last years info minus 4).