Zverev gets himself in these 5 set battles because he does not have the weapons that the big 3 have to win matches easy it will cost him later in the event if he wins.
I think in general the argument is that he does have the weapons that the big 3 have to win matches easy. He's 6 foot friggin 6. His first serve is devastating when he gets it in. Great backhand. Great forehand. Moves much better than most of the 6'5" guys to come before him.
He's just not getting it done. Struggling mentally in his (still) early days. Probably just not dealing with the huge amount of expectation that gets heaped on him. He's still figuring out how to dominate. He's young. Most of the players he faces have more experience than him. That's not really the case with Tiafoe. But we know Tiafoe is very good. Albot? Not so much. But Albot clearly knew what everyone knows this year. Zverev is struggling to play his best tennis. And he was able to capitalize. For two sets.
I agree it will hurt him later in the tournament. But theoretically he should have plenty of rest for his young body. So if he gets to Nadal and can't beat him, it's because Nadal is still better on the day. Not because he played some 5 setters.
It took Fed to almost 22 to win his first slam. Nadal and Djokovic both definitely beat that by a good bit. But neither of them, or Fed, knew how to dominate week in and week out immediately after that (though Nadal on clay was always pretty dominating.) It takes time to get to that point. It takes A LOT of matches. And confidence. Which Zverev definitely doesn't have a ton of right now. He's still gotta develop his sense of urgency and intensity. He doesn't have that same .... "waiting to pounce and maul lion/tiger/jaguar" presence that players feel when Fed, Djokovic, or Nadal are returning.