Depends on your personal preference, tbh. Would you rather have an annual system with three subjects for the first two years, then pathology, pharm and micro and so on from third year. A degree from Karachi University, and if you are okay with the locality of KMDC go for KMDC

If you would rather have a semester system/modular system where you focus on all the subjects from anatomy to pathology from first year, a degree from JSMU, and if you are okay with the locality of SMC go for SMC

And haha at the "bears no international importance" part. Darling, there's a an accredited website which contains the Directory of all the medical schools in the world. ie World Directory of Medical Schools. Here's SMC in it >
https://search.wdoms.org/home/SchoolDetail/F0001289
Whenever you have been told anything from anyone, always verify from the primary source.

If you want to be in Dow more than anything you can go ahead, take that gap year and take a chance with next year's admission. But keep this in mind; ten points from your A level/inter scores will be deducted for that year :/ (just how it is, sadly)
I would suggest you go for SMC rather than KMDC. (what with me being biased). Your wish entirely in the end, they are both fine institutions