Think a lot of that was down to the bog they were playing on. Every step had to be calculated to within a 0.3 micron tolerance. Everyone struggled with it, even (and probably especially) Bayern players. It impacts everything from your push off step (which affects your power running), your touch, your dribbling (most of the midfield was cut up by halftime), your passing, even your vision, as you have to watch the ball all the way to your feet (unlike a decent pitch when you can just automatically extrapolate where it is going and scan the pitch before it gets to you). It delays everything when you have the ball. Defenders don’t have most of those issues as they charge the ball and/or players down (though, they were slipping everywhere, too, just ask Upamecano, Kimmich, Ake, and Akanji).
And anyone that has played football for any decent amount of time has run 8 km on a pitch like that and been absolutely knackered.
I wouldn’t use this match as a gauge of his ability or form.
After watching Tuchel’s post-match interview where he throws his grounds staff under the bus, I am not entirely sure it wasn’t his idea to make the pitch like that. It just backfired spectacularly and now he’s trying to deflect blame.