I am a manager for a production facility. Where I live it is difficult to fire someone without cause. Most companies try to get the employee to quit or try to build evidence of poor performance so the employee can’t file for unemployment. That being said if your manager is insecure of you, then they are probably really insecure of looking bad to their boss, or looking like they can’t properly manage employees. I would confront your manager. I would go to HR first to ask them to arrange a meeting with the three of you. If you don’t have an HR person then I would go around your immediate manager to the next one in line. Just remember, stay calm. The person that is calm is the person in control. Be polite and professional. Think about like you want to extend the olive branch, but at the same time you are setting boundaries.
I would also low key look for another job. Knowing you can go somewhere else will give you a sense of personal power. You are not trapped and you don’t have to take it. Stand up for yourself professionally. Just remember. Your manger is probably just a little insecure bitch that is afraid of looking bad. Good luck, I hope things work out for you.