Havertz was a project signing, never going to dominate straight away. Majority of his issues come down to a lack of physicality. Decision making, ball retention, complacency etc. all come down to time on the ball, being able to ride challenges & impose himself.

Havertz can dictate in the final third, glides on the ball, deft touch, brilliant decision making (execution needs work), top G/A output. He's adjusting to a new league, system + position. #8 requires much more intensity, sprints, ability to ride challenges, endurance etc.

Truth is, Chelsea bought him knowing this. They expected this level of performance, he's the best signing (long-term) they made this summer. Internal expectations will be 12-18 months before Havertz is truly ready. Remarkably similar situation to Félix, expect a similar outcome.