I don't think this catch is as great as people think. And it certainly isn't as good as Willie Mays' catch. It's a pretty good catch I'll give him that. But it could have been a much easier catch if he took a better route to the ball.
It reminds me of people losing their shit when Andruw Jones was making all of those diving catches. In many cases he would make a bad read on the ball off of the bat and in other cases he would clearly slowdown to dive for it.
So Juan Lagares made a pretty good catch, but stop comparing it to Willie Mays. This dude's first few steps set him up for this.