Not to sound arrogant or anything, because I know many fine, intelligent teachers, but when I was in college it was kind of a joke that if you couldn’t make it in any other degree program you got an educator degree.
When I was in H/S years ago I had a real problem with math. I had a teacher who was so afraid of the “students” he would just let us do whatever we wanted. When he had a breakdown we got a sub teacher who was using his vacation time to teach. He was a Airline Pilot And Vet from the Korean War, no nonsense, totally impressive from the minute he entered the classroom you knew he was not someone you wanted to mess with. Within those two weeks I learned more about math than I had in the previous two years. What a great teacher he was. Problem today is he would not be allowed to teach because he did not have a “Teaching Certificate”