I'll be departing my job at the end of the month. I had too many roles, affecting too many pieces of engineering, and my title didn't reflect my work. I needed to go down to a 4 day work week and have my title reflect my roles, but my manager attempted to call my bluff and essentially said it's not going to happen. I hinted about what my decision would have to be if these accomodations couldn't be made, but he didn't…
Re "trust is broken" - I used to think like this and I understand, but I would encourage you to try a more nuanced POV. There's a decent chance your manager was simply not allowed to accommodate you, and your verbal notice unlocked options from upper management.
A trusted party wouldn’t hesitate to explain the situation.