She should apply to every film school she wants to attend, and not worry about the HS film teacher.
Her portfolio/essays will articulate her creative voice more convincingly than the HS film teacher’s opinion. As mentioned, the criticism will prepare her for film school.
My son is Spring Admit to SCA, starting this Jan. His school didn’t offer any film classes, so he got involved in the local film community and created a Film Freeway account to get familiar with the festival circuit. He interned for a local wedding videographer.
Just sharing a few ideas that can help demonstrate interest if the HS film teacher isn’t a LOR good resource.