In a deeper role, Havertz continued to excel in terms of ball progression and defensive work compared to his peers
That's not what the graph says. The graph says that compared to other central midfielders, Havertz managed very few tackles and virtually no interceptions. The only defensive actions he did well on was clearances and aerial duels, presumably using his height during defensive corners, etc.
The player he's presumably replacing (Xhaka) played his entire career as a central midfielder, and only in his last season really ventured forward to play a bit more as an attacking midfielder. When Xhaka was Havertz's age, he didn't use great judgement when doing his midfield defensive duties, but at least he knew it was his job and did it with enthusiasm. As far as I can tell, Havertz hasn't played much as a central midfielder. For Bayer Leverkusen, he started as a CAM and then played for a while as a striker. For Chelsea he was always played as an attacker, mostly a striker.
The main concern I have with him is whether he can successfully do the defensive basics: marking, intercepting and tackling as a central midfielder.