Wow, you caught me in a typo. It’s 37/36 = ~1.03.
Great job.
I don’t know why you decided to cherry pick GM, when Diamond is a Sample size 160 times as large (actually I do, it’s because they’re 31% there). But let’s say you’re right. Fine.
Terran is played at a rate of 1.03 more activity than average, for 1.06 times more experience, and receives .91 as much MMR (since you want to discount the lower leagues entirely.
Ergo, Terran is:
(1.03x1.06)/.91=1.1997
Or, that is, roughly 20% more difficult than the other races. Even by the incredibly generous metrics you gave for yourself.
That means a 4500 MMR Terran would, if any other race, be roughly 5400, or about top 70 GM.