Multiple Cs should I do a DIY postbacc or SMP

I currently have a BCPM of a 2.25 due to multiple Cs in premed courses and a undergrad gpa of a 3.36, i am currently taking physics and I still need to take physics 2 and biochem. With hopes that I do well in my last set of semesters of undergrad fall 2019-fall 2020 i can raise my gpa. I used the NYU BCPM calculator and to get my science gpa to a 3.0 i would need to get an A in physics 1&2 and biochem and take three additional science courses and Ace those as well. I know my stats are not competitive and I don’t plan to take the MCAT until I am ready to apply. I have plans to do a academic enhancement masters programs to help my chances of getting into medical school. However after graduation in fall 2020 I will have 8 months off so I was wondering if should I do a DIY postbacc and take additional upper level sciences before pursuing the masters degree? Or just pursue the masters degree?