Most of my new career is teaching parents how to be parents. And usually, they can't do this because of trauma that they experienced as kids and they are continuing the pattern. Or, there's generations of unaddressed mental health issues, substance abuse, or alcoholism.
You are right to let it go. It's bigger than all of us. But, some of those kids will remember your efforts and appreciate them. During my last year of teaching I had 2 girls who were seniors in HS come back and visit me to say, "We were so horrible to you; hope you can forgive us."