In Demon Slayer, if demons get stronger as they eat humans, could a demon ever surpass Muzan in power if they ate enough humans?

 

Nope, eating just regular people is not going to give you anywhere near the amount of power to rival Muzan.

Not only that but Muzan would never let someone to just get stronger then him and anyone who has his blood he can control however he wishes like read there thoughts, know there location and anything that has to do with privacy he knows.

Even Kokushibo, the person with the highest concentration of Muzan blood bows down to him and follows his orders simply because he knows he cannot win.

Even if we did assume that it was possible for them to gain that much power, Muzan’s paranoia wouldn’t allow it and he would kill them which he can do since they have his cells.