You have Type 2 diabetes and a low A1c, which suggests that you have some basal and/or second phase insulin response left.
Since that is the case, eating no carbs will allow your residual insulin secretion to catch up with that high and lower it, so eating a no or low carb meal will work well.
It is only when people have no insulin secretion as in Type 1 or advanced Type 2 (where they have allowed glucose toxicity from blood sugars over 180 mg/dl day in and day out to kill more beta cells) that blood sugar will continue to rise even without carbs being eaten.
Metformin can be very helpful because it blocks the dumping of glucose by the liver which is a problem for many of us. I’m not significantly insulin resistant, but boy does my liver like to dump glucose so metformin will make a difference in my post-meal numbers.
It’s cheap and worth trying if you have achieved that great A1c by cutting out almost all carbs and are having problems even then.
OTOH, I found that after three years of excellent results with metformin, it started to give me undesireable side effects and I had to stop taking it. So it might be worth waiting until you really need it to start it. Hard to say.