Olympic TT wasn't an outlier, it was like just over 1s/min over Kung and Ganna on a very hilly parcours, plus I think he carried less fatigue from the Tour and road race. Dumoulin got 2nd on limited preperation, I don't think the field performed that strongly.
Vuelta TT is a much more useful data point, but I also think the range in such flat TTs is gonna be pretty narrow. Rog probably wasn't great in that TT, the gap in the flat TTs should be 1s/min on the low and and 1.5s/min on the higher end in the first 2 TTs, which is gonna be like a 40s difference which in turn doesn't change that much.
The mountains have a much bigger margin of error, and there also lie tactical mistakes not to repeat. Like when you're bad, you should not try to follow Evenepoel, because you'll blow up 100% of the time every time and maximize your own losses. That's especially hard against Evenepoel who loves to go very hard early on a climb. I haven't really checked if he does a positive split when he does apart from Praeres where he very clearly did.
I think the plan should be to try to limit losses and mainly go for bonus seconds and last km roglstomps before you get to the big mountains starting with Crans Montana. Then the time gap and form should dictate when you start attacking.