The thing with Remco is that his peaks are absolutely incredible, argubly higher than Roglic's, but he has massively struggled to string those together over an entire GT. He won the Vuelta once, but those bad days towards the end of the 2nd week don't end well for him if he is racing Vingegaard, Pogacar and Roglic in better shape. He couldn't sustain his level throughout the 2021 Giro, cracked massively in the high mountains of last years Vuelta and some people probably aren't 100% convinced him dropping in the Giro was an early covid symptom.
Now there are plausible explanations for all of those things, but once someone fails to consistently perform in a GT so many times, one starts wondering whether this is just an inherent weakness of him. I don't think anyone of us can say for sure, which is why I think he is such an interesting wildcard going into the Tour. If he can ride like in LBL 2023 for 21 days he might pose a huge problem for Vingegaard and Pogacar both not in perfect condition. But if he has done it for 19 days I will still not be certain he can do it on day 20 as well.