I know I've seen some very different methods and lessons in curriculum from my kids and grandkids.

Much of it is just different strategy and emphasis in specific areas. Some of it is introducing new concepts that prepare them for more advanced things later.

However Education departments are always state by state with federal funding in support and they set the mandates and curriculum.
Fortunately my state is a bit more progressive than most in making education a priority for communities and their school districts. But it can differ greatly between school districts too.

Magnet and Charter schools with open enrollment per city are very common where I live. My kids went to different high schools each for different reasons.