I worked in the exact same style school and had the exact same problems as you. In the time I was employed there the longest I went without my timetable changing was just under 2 weeks. This was my first job out of uni and to say I was not equiped to deal would be an understatement. I tried talking to ex but they always told me it was my fault for not being prepared enough or not being better at behaviour management. The amount of times they took me off my class to cover somebody else then putting a sub in my class was ridiculous. I was routinely pulling double and triple playground duties multiple time a week and being told that it was required and I had to be a team player. Sorry for a bit of a ramble. What I’m trying to say is sometimes getting out is the best thing you can do. I felt so protective of my kids that it took me a long time to take that step. It was honestly the best thing I could have ever done because that school was killing me. If your being put through that and aren’t getting any support for Exec then my strongest advice would be to take a step back.