At the January of the current year, I have submitted a paper to a high-rank math journal. After around 10 weeks review time and 4 weeks editorial time, a decision of reject-and-resubmit was made (1 minor revise, 2 major revise and one reject-and-resubmit were the decision of reviewers).
I answered the comments, which, in my opinion, significantly improved the paper in a than response letter with more than fifty pages. For example, I proved a set of new interesting theorems and lemmas in the revised version of the paper in answer to some of the comments.
From the submission of the revised paper, nearly 18 weeks have been passed, during which the paper is under the review. I wonder why such a long time is necessary for a journal which gives its reviewers just an 8-week reviewing time.
Does this mean that the probability of acceptance of my paper, is high or low? What is happening in the journal for my paper? I am very much dependent on this paper to finish my Ph.D., and for my job. I worked very very hard but unfortunately at a low-ranking university. Will they judge my paper by the rank of my university or my advisor (co-author)?
My supervisor urges me not to contact the journal editor for the decision about the paper since they may get angry and reject the paper.
My main goal is to sooner defend the thesis as I am under immense pressure. My university needs at least one JCR Q1 or Q2 paper to be able to defend the thesis and graduate.
As this may take more time, my main question is: what is your advice for me, assume rejection of this paper and work on a new paper? Or assume acceptance, or revise and work on writing my Ph.D. thesis? Since the draft of my thesis is dependent on this choice very much, this decision is very crucial for me.
What would you do if you were me? In other words, what is the probability of rejection for a long-time-review in the revised version of a manuscript?