I guess that you haven't fully understood the complete problem space of everything that a teacher has to master in order to be effective, and everything that a

I guess that you haven't fully understood the complete problem space of everything that a teacher has to master in order to be effective, and everything that a school has to provide resources for (including other areas of training). Classroom teaching is not highly dependent on technology and low-tech solutions are often better. Your suggested solution asks teachers to give up a day of their time (unpaid?) for what you think is important, without listening to what teachers actually find difficult about their jobs. Even if what you are saying is right and genuinely helpful, it won't immediately look like a good solution to the teachers or to the administration.