Masters at Harvard Extension School as an intermediate step to enter Masters at Harvard/ MIT/Stanford

I am software engineer with 5 years of experience, 26 years old, and I have Bachelors degree in computer science (outside US). I wanted to enter MBA at top School, however now am thinking about masters degree in data science at top school. Being a part of top US school was my dream science childhood, however I am afraid that they will not let me study there because of my weak background. I have GRE 333 (170 quant, 163 verbal), 108 TOEFL. 3.18 GPA. As far as I am concerned, they are not considering my test scores, and are focused on my academic achievements, and it is my weakness. Now I am thinking about getting Masters at Harvaro Extension School, complete it with 4.0 GPA, do some research, publish some papers and so on, eventually, enhancing my academic achievements. Is it a good strategy to enter graduate programs at top school? Thank you in advance!