I'm not type 2 so can't comment on metformin but I struggled to get my HBA1C down until I tried low carb.
Personally I only eat carbs 2 or 3 days a week, my HBA1C was over 13 and is now 5.5 which is technically in the not diabetic range. But figure out what works best for you.
I've found that taking carbs and other ultra processed foods out works great, you get less hungry eating fewer carbs, some hormone is triggered when you consume carbs, to make you want to eat more. The best example I can give of this is when you go to a restaurant and people eat ALL of the chips (fries) even though they've eaten a load of food already.
But if you're low carb and eating mainly protein, healthy fats and fibre you don't get that hormone asking for more food, you feel fuller easier and most importantly your blood sugars lower and are more stable.
My diabetes care team were reluctant to let me go low carb as its "hard to stick to" so this is all my own doing after doing a lot of research, so you may not get told to do it either, but maybe that's what they meant with an "8 week blood sugar diet"?
To go a bit deeper on it, in case anyone is curious, I've found eating carbs as your evening meal on the day you do eat carbs is best, helps with sleep - not sure on the mechanism and could just be me, but it works for me so might for others.
Good luck.