An argument I've heard is that since hydration breaks can affect the game, if you are going to have them they should be mandatory and at the same time in all games in a tournament rather than doing them like they did when they were originally introduced in 2014. Then they were only done in games when the conditions on the field got dangerous.

Not all stadiums were enclosed

Telling of what? I imagine if you're running around like eg Ronaldo would be during a game, it doesn't matter how air conditioned the space is, he'd still need to hydrate, on account of all the running that happens. I'm no football expert, but I'm lead to believe that does happen during matches.