Yes, but Pogi didn't ride full gas, at least not in the Giro2 things. Kuss didn't ride full gas (by that I mean fighting for the GC) during Giro and Tour. In Vuelta, Jumbo gifted him a GC win.
And, Kuss was probably in his best-ever form in the Vuelta. Yes, he was gifted the win, but, ordinarily, you'd expect Vingegaard and Roglic to beat him. He was slightly worse than them because he is not as good a rider, not because of fatigue. This shows it's possible for Pogi to be in close to his best form