I have T1 diabetes and wear a GCM so have a continuous view of my blood sugar levels. I also go to the gym and exercise otherwise.

My experience is somewhat different. Even walking is more effective than chess presses or arm exercises for immediately reducing blood sugar.

After an hour or so of more intense aerobic exercise I find it basically impossible to avoid a hypo (low blood sugar).

Simplistically if the effect of exercise on blood glucose is roughly proportional to Volume of muscle engaged x Length of time engaged, things like running should be very effective. The bulk of your muscle is in your lower body and you’re continuously engaging it.

I suspect any decently intense exercise can have a moderate lowering effect on blood sugar levels after the immediate drop seen when you’re exercising, but the effective isn’t huge.