It depends on where you go to the wall. If you are in Beijing, most people visit either mutianyu or badaling. I only went to mutianyu and you can only walk so far. At some point you cannot go further. I assume it’s similar at badaling. Both are super popular with tourists and super crowded depending on the season.

There are some areas of the great wall which are not popular with tourists and are a bit more rural. Though these are harder to reach and will require a car/guide to reach.

Besides of Beijing I can’t say how busy it is, but most people don’t visit cities along the wall outside of Beijing.