Yes but prior to that Havertz played as one of two tens in a 3-4-2-1 behind Werner/Lukaku, e. g. in the UCL final. That's pretty much the exact same position Sancho occupied in Favre's 3-4-2-1 when Hakimi was still there. His competitors for this position, if he was to play for Chelsea instead of Havertz, would be Mount, Ziyech and maybe Pulisic. You never fully know but I think everything points towards the assumption he'd be a clear starter.
I mean, let's not Sancho outperformed many proven world class attacking players in the Bundesliga over the last few years. Reus, Gnabry, Coman, Sané, Havertz, Werner, etc. were all quite clearly worse than him.