Need suggestions on how to proceed with my AI career

Please excuse me, if I am raving. I came to HN as my last resort. A little background, I have a CS Undegraduate degree. I decided to pursue AI, when I was in third year of UG. which was two years ago. In the meantime, I have secured 2 internships and 2 full time jobs, all of them are from very prominent companies with very good pay. Still, I very much want to work on R&D side of AI. Therefore my intermediate goal was to pursue Masters in A.I, which would give me good Academic understanding of A.I and also give me opportunity for research. With that decided, I am currently in a tuff spot, Even though I have good Industry experience and good GRE score (168Q, 164V), my UG GPA is under the bridge with 2.7 GPA, which might very well rob me of pursuing MS in top universities. Therefore I thought i can improve my chances of getting into good MS programs by pursing stanford AI graduate certificate. This is very expensive to me, therefore I have to take a decision on whether this is necessary or not. My motive was to pursue this and write good AI papers to increase my chance of getting into top universities. You might ask, 'why not start writing papers now?' I have completed Deeplearning.ai 5 part specilisation, Udacity NLP Nanodegree and have taken MIT OCW on Mathematics. I am very much skilled in building and tweaking models with frameworks and also on understanding how architectures work in detail but I am still a novice on full blown mathematical side of it, which I dearly want to learn, I am hoping that stanford graduate course would be rigorous in that way, to help me be proficient in A.I I have also looked at omscs from GT, but as my goal was to indirectly pursue research, I ruled this out. Any suggestions or inputs on this would be quite helpful to me.