In the mountains he lost more than 5%. He gained some power in the flats. Go figure.I don't think he looks heavy or really out of form. It just looks like he's lost about 5% of his engine, so at the end of a stage, which basically means that he can make it to the final selection on an MTF but will gradually go backward. His TT'ing is also down. And, if he does have a great day, he's inevitably flat on the following stage. I don't think that's something he'll be able to get back.
But, even a diminished Nairo is a top 5-10 GT talent, so for Arkea that's basically a win right there. Even if he finishes, say, 8th at the TdF or even 5th at the Giro, that's a better result than Barguil will get them.
Tours ans Vuelta with more crosswinds and he has a chance to win it. LOL.