Also continue with FOIA requests. All teachers in every school I’ve worked at are made aware that any email on school servers or using a school email address are discoverable. Go get’em.
What you said is 100% true.
I speak from experience as a recently retired 33-year veteran of the public schools.
We were told when the district gave us school e mails years ago that these were NOT private - and warned not to use them for private business.
I learned this lesson when I used my school e mail to ask another teacher what time we were meeting later for dinner.
Got a response from a moderator somewhere that I was NOT to use school e mail for personal business.
Everything you write is being read - and can be made public.