Barring crashes or other things that would ruin it, I expect this race will be decided by one of Roglic and Evenepoel breaking the other in one of the big mountain stages and taking, say, two minutes in the process. As good as Evenepoel was last Vuelta, he didn't have to face this magnitude of climbing, whereas Roglic destroyed everyone on the way to Covadonga the last time he got to do a big GT mountain stage in perfect health. In fact, I think Evenepoel's Vuelta-winning climbing was less impressive than Roglic' climbing in the 2019 and 2021 Vueltas, as well as the 2020 Tour. Moreover, I don't think Roglic has declined much, if at all, compared to that (rather it's Pogacar and Vingegaard who have improved).
So if anything, Evenepoel needs to break new ground to be the one to break the other rather than the other way round - ground that he didn't break in Catalunya. Now Catalunya definitely isn't a perfect predictor and Evenepoel still has room to grow in terms of his climbing, but as someone who voted for Evenepoel ahead of last year's Vuelta, I still have a bit more faith in Roglic for now when push comes to shove in the Alps.