to / for?

[maoyueh]

Are the sentences below correct and natural? Thank you.

1. To many students nowadays, striking a balance between schoolwork and extracurricular activities is a big challenge.
2. For many students nowadays, striking a balance between schoolwork and extracurricular activities is a big challenge.
3. To many students nowadays, it is a big challenge to strike a balance between schoolwork and extracurricular activities.
4. For many students nowadays, it is a big challenge to strike a balance between schoolwork and extracurricular activities.

[konungursvia]

To me they are all correct, though the first two sound more authentically idiomatic.