I don't have access to data to back this up, but my impression with qualy was that as the cloud cover increased during the session, the gap to mclaren reduced (and also the track got faster).
I'm not just talking about Max, but more like the entire field vs McLaren.
Maybe MyLaren's level could have been reached at low 30°C (and beating track record).
This just further strengthens the impressions that McLAren has a serious advantage in the hot.
I think this effect is stronger than flexiwing etc. It is entirely possible that McLaren lost like a tenth or so on flexiwings, and it will show when it is colder.
But as long as it is hot, they are unbeatable. Much will depend on RedBull's next update (supposedly) aiming for this.
If McLaren have similar advantage in colder Canada, then it's game over.