Toxic leadership leads to constant turnover and instability - Curriculum Developer TechSmart (WA) Employee Review

I started at TechSmart 3 years ago in 2023 and was on the Curriculum team. At that point, the team was made up of 7 people (including myself). Since then, every single one of my coworkers has either been let go or quit. Including 3 new coworkers who joined the team in the last year. I had 4 managers in 3 years. I was the last Curriculum Developer AND staff member left on the team when I was let go. I received an email from the CEO to notify me after I returned from my first real vacation in months. One month prior to my release I was offered a promotion to a management position. I declined the promotion because it was done via a Slack message and I was told I would only be presented with official offer letter once I accepted the position. I was also not going to receive the new salary rate until 2 months later with no backpay. My coworker had accepted a similar offer on good faith but was let go before he saw any salary increase. The CEO is now creating curriculum himself. He does not work well with others, is never satisfied, and does not respect or acknowledge the work of so many talented people. There is no real HR department (HR is now the CEO's wife). He has hired his own family members while never replacing real desperately needed positions. Both his wife and son have been added to the team without any real experience.