Getting a pre-assist with a long switch and playing a lobbed through ball behind the defense aren't contributing to offense now? Those are two passes that Alba has barely done in his career let alone in a single game.
It's not just about just running with your head down to overlap->cross. Being an offensive fullback requires you to read the situation and play into space in a way that keeps the attack going and progresses it. Miranda's reading of the game was superb for his debut.
There were a number of plays not on that highlights comp where Miranda had linkups/forward passes down the flank under tight pressure that were very nice. I actually think the comp missed a fair bit of his impressive play, and he was showing the ability to progress the ball under any pressure or circumstances. If you insist on comparing him to the best, Marcelo often plays those passes up the flank when it calls for it to stretch the defense further and keep things moving forward. Alba doesn't, and just insists with low efficiency crosses on overlaps where he rarely ever contributes individually. Marcelo also switches the play ALL the time for RM, that's a big part of how they keep the defenses stretched and on the back foot.
You probably just saw that shit overhit throughball by Denis and complained about how "unathletic" he is without paying attention to much else.
This comp is much more complete. Shows how composed he is in a number of different scenarios in buildup and with different kinds of passes. And all of this was in only 45 mins of play, hardly the craziest thing that he didn't have an overlap->cross in one half.