I have read through your posts again and I would imagine your endo diagnosed you from this hypo episode after your OGTT.
Other than that and your insulin tests, have you had further diagnostic tests, such as mixed meal, have you had a allergy test?
And the last one is the 72 hours fasting test, I take it you haven't?
I have heard of flat line hypoglycaemia and idiopathic postprandial syndrome. These are similar conditions and symptoms but you don't get spikes and you don't go hypo.
A glucose tolerance test works for diagnosis because the 75g of glucose solution is very quickly absorbed and the spike is rapid, mine was between 30 &45 minutes, the hypo happens for me around the third hour to the fourth. Hence the recommended meals every three hours but you still get the symptoms and the hypo if you forget to eat and I found that I was eating too much.
The idea behind low carb diet is that the spike doesn't happen, so the overshoot doesn't happen, no hypos! This is because protein fats and above ground vegetables will not raise glucose levels
As I said, if you have RH, you are carb intolerant.
So test the carbs, see what happens, a food diary is a great way of tracking your results. I went through weeks of trial and error with my favourite foods.
I found so called healthy complex carbs are not healthy for me.
Finding your healthy foods is something that you probably will have to do to get some answers.
Stay safe