@Colhammo Sorry to read about your daughter's symptoms and likely diagnosis.
Reading the screenshots you quote about not using HbA1C to diagnose diabetes in children. This does not say that the test should not be used but that the test shouldn't be used for diagnosis.
I suspect (although I am not a doctor), this is because diabetes symptoms come on very quickly for children as the insulin producing cells are killed much quicker than with adults. Therefore, a test which provides an average over the last 3 months may miss a diagnosis. This is different to a HBA1C misdiagnosing diabetes.
Even after eating a bowl of cereal, a healthy pancreas would be able to produce enough insulin to bring her blood sugars down to lower than 27. A healthy pancreas would not see double figures. A fasting test is not needed when levels are this high.
Diabetes is scary but the statistics that are available about complications, lifespan, etc. are based on historic data. Data from the times when we did not have fast acting insulin, when blood sugar tests were taken from urine, when technology did not include CGMs and insulin pumps. I am confident with my future with diabetes because all these things are available now and I expect more to become available over my life.
People with Type 1 diabetes are competing in the Olympics, playing football and rugby for their country, performing in Internationally renowned bands, traveling the world, ...
Type 1 diabetes should not hold your daughter back (although misconceptions about it may) and, if managed, should not lead to further health problems.