In case the cornering was indeed a problem, then you could well lose more than 10 seconds over the course of the TT. Taking a high speed corner too wide, or slow down too much, going into the corner at less than optimal speed and having to make up for that coming out of the corner, will cost you 10 meters or more. You start losing distance by braking too soon/hard, you lose distance by a less than ideal trajectory, and you lose distance coming out of the corner too slow and it will take longer to get back to top speed.
Though we did see Evenepoel take some corners less than great, i don't think we got to follow him closely enough to be able to determine whether this was an issue throughout the race. But if it was, then he could certainly have lost the race there.
EDIT: If you look at this strava Segment, you can see he loses a full 2 seconds in just the last corner to Bissegger, who takes the actual corner almost 10kmh faster. So it does look like he did indeed lose this in the technical sections of the course.