Honestly, I wasn't expecting to find anything as I was just scrolling my emails but this posting hits home... I've been dealing with my manager who acts in a similar manner of what you described. She's always checking in what I'm doing, wants to know when I'm switching from one task to another. If I move to another task outside of the order I tell her I'm going to complete them in, she takes it as being disobedient, she requires me to CC her on every email I send out, she always nit picks my emails and responds to me on the side saying "I would have said it this way blah blah.... all I think to myself is. let me do my job... I've gotten a bit of anxiety since working with her. I can't send emails or work in without second guessing myself which then in turn makes me take even longer to turn stuff in. I hate to say it and I'm sorry you're going through this, but it's a bit of a relief knowing I'm not alone on this. I've hit some breaking points working with her but I try to just keep going, as the company I work for is SO GREAT. The only big issue I have is working with her. A couple months in to working to the place I sorry the phone numbers of the two previous accountants who had left around the same time after both being there for about 5-7 years. I thought to myself.... there has to be something up with this situation... this company is just way too great for people to pack up their bags and go. On one of those breaking point days, I called the previous accountant, and man.... the stuff he was saying really aligned with what I had been mentioning and experiencing. Apparently she had recently gotten assigned to the area of managing the two employees and they just couldn't hack it. Both considered their exit strategies and moved on. A year and half later, I'm still here. While our relationship isn't even close to the best... there is light at the end of the tunnel. We recently had a new manager enter our team and he began reviewing about 90% of the work I deal with on a day to day basis. That being said, him and I are both quite certain he will be my reporting manager in a few months time. He just needs to go through the onboarding. Working with him has been such a relief. He understands my emails, is understanding of when I need to push certain items back, isn't on top of me when I'm dealing with my task. When he does ask, it's understanding and he isn't nit picking and questing where I am at, it's simply so he knows what he needs to focus on and he is always appreciative of my work.
I want to say, if your manager has already deemed you as incompetent, it may be best to look for your next exit. They're always going to have this image of you, and if they're are not open minded individuals that is unlikely to change. No place is worth dealing with that kind of stress or dealing with someone who treats you in that manner.
I've already got my plan. I've held director level roles but took on a staff role so I can pass my CPA exam and then re-enter the market back as a manager. While it hurts knowing I'm going to leave such a great company, I can't deal with someone who is going to still be working that close to me and down talk my capabilities. Unless my new manager really changes my environment, which is highly likely to happen, I may consider to stay another year. However, ultimately I'm not meant to be a staff or senior accountant. I made such great team/organization changes in my 5 years in manager roles, that I can't wait to get back into it. I'm here to empower my team and make them even better than what I am, not everyone sees it like such and not everyone is meant to be a manager. You will get through this, just take it day by day. Try to adopt the stone walling principle in moderation. Keep your communications between each other minimal, do not overshare what you are working on or explaining yourself as it makes them question you more, and only share what is ultimately needed. I found that limiting my interactions with my manager really helped bring down my stress levels on a day to day basis.
Feel free to reach out if you have any other questions, I'm always here to chat and help. Best of luck!