PhD supervisor stalling research paper submission
No one here can judge whether your supervisor is right or wrong. Perhaps your paper really isn't yet ready. I don't know your field, of course, and don't know why it is important to you to submit the paper now rather than later. 

Your first consideration should be your examinations, I think, and completing your degree. Perhaps publishing the paper is essential to that process, but you don't indicate that. 

But, few students really prosper by directly going against their supervisors. It just isn't a productive career path. And, depending on your field, cutting your supervisor out of authorship might be considered unethical, but even if not, might be a career killer. 

Having a supervisor who is happy with you and your work is much more productive. And giving a lot of feedback on your paper is, in most cases, a positive thing. 

Once you finish the degree you get to make your own decisions, of course.