Are classes harder for middle school in a Christian Private School vs a Public School?

Edit: I was thinking about a highly funded public school with advanced classes vs high tuition Christian school. I am in FL that promotes school choice. Our schools have programs/tracks, and what my kid wants to be is where we are zoned for. Talented classes are basically gifted classes for kids who all make 5’s on the state class. My daughter keeps saying her friend’s classes are harder than her (my daughter’s) classes.

My daughter has a friend that goes to a very expensive private Christian school. They are both 7th graders. My daughter goes to the local public school and is in talented classes making straight A’s currently. Her friend isn’t doing well in school with a D in English so far and the rest are B’s. Daughter says that her friend’s classes must be harder for her not doing well. I would assume they wouldn’t be as hard as the classes she is taking.

Both of them shared a lot of classes in elementary school and made similar grades, but then middle school came and daughter is soaring while her friend is having a tough time.

I sometimes wonder if my daughter’s classes are actually that hard or the classes are what they should be learning if a teacher had a room full of hardworking kids, compared to standard.

So are classes at a private school harder? Or is it all subjective?