Brendan, that game 2 was strange. But I think MC may actually have prepared the opening! The position after 11...Qb8 is indeed terrifying for Black (imagine having that vs. Firouzja!). However, if you play through subsequent moves with the computer on, White didn't really go astray until 16. Rd4 (Qb3 was better), and throughout the sequence White continually had only one move to keep a significant advantage.
Seems like a modern trend in opening preparation, especially in rapid games, is to willingly go for inferior lines provided the refutation is difficult to find over the board. And when Magnus feels in good form, he's willing to roll the dice in some dodgy positions.
MC's two White wins (games 1 and 3) were smooth and convincing. Though game 3 should likely be discounted because Alireza had to win at all costs.