Reading your cover letter is like pushing a river upstream. If I were you, I will arrange the words and sentences into a flowing composition. You can start like this:
In search of a career challenge, I find the position of xxxxx exciting.
I worked for two years as an NGO research associate and in the completion of my doctoral study, I believe I will be an excellent candidate for the position.
(I think you can continue from here. Your first paragraph implies that you have not completed yet your doctorate. But the next paragraph implies something else. Point is, make your cover letter as concise and straightforward as possible. You do not need to put so many details because your employer can find them in your resume.)
Student or Learner