Schools in the US are run at a very local level, and so there's a HUGE amount of variance across the nation.

That said: The busses really are yellow. That part is accurate.

The activities and stuff is accurate, just always turned up to 11.

This is the type of question I receive if non Japanese people ask: "Are high schools in Japan like anime?" and the answer I give is: "no" since that's not reflective of what actual school life is.

You mean Japanese schools don't usually have student councils that rival state governments in political power?

It's pretty much the same kind of thing as Japanese schools portrayed in anime: the major points are often accurate, but the specifics are exaggerated and certain things get disproportionate focus, because those are the "most entertaining" parts.

Do many Japanese schools have culture festivals? Yes. Is it every Japanese highschoolers most important event of the year where major life changing events happen? No.

Do many US highschools have prom and homecoming? Yes. Is it the highlight of every teenager's school experience? No.

It's all based on something real, but it's exaggerated, and definitely not a universal experience for everyone everywhere.

I should also note that the stereotypical American highschool you see in TV shows and movies is heavily modeled after 70s/80s/90s school life, because those are the people creating the shows/movies.

The whole jocks & bullies thing was alive and well when I was in public school on the US.

The general description you gave is very accurate to American schools. How it goes about on TV is not.