Sorry but his mistake against Liverpool has nothing to do with being overplayed.
How can you be sure about that?
It was about decision-making, and when you are being overplayed, your decision-making suffers. E.g., Van Dyke made several big mistakes toward the end of 19/20 which cost Liverpool our record of 100 pts. He played in almost all games that season, i.e. he was overplayed. Rodri was overplayed in 20/21 and lost form to the extent that Pep didn't use him vs PSG at home and Chelsea in the CL final.
Even the best defenders are bound to make bad mistakes when they are not mentally fresh enough. Mental fatigue may be a bigger problem for players than physical tiredness. Cancelo is fit and recovers better than virtually any City player, but he might be a bit tired mentally wise.