You're right, initial diagnosis is made based on information at hand. As more information becomes available, the diagnosis may change.
The good news is that for most of us, lowering carb intake to the 30 - 40 g range per day brings glucose levels back down, for some in 1 week, for people like myself, 2 to 4 weeks with gradual improvement over the next year. As for your concerns about diabetic ketoacidosis or DKA, this can be monitored for with daily glucose testing, upon waking, prior to bed, prior to and 1 and 2 hours after each meal, prior to and after each walk.
That little glucose meter is so empowering. It gives us the feedback we need to figure out what's helping and what's not in real time. No waiting for a doctor to order a lab test.
The first month following diagnosis is loaded with conflicting emotions and angst. I was lucky. A few weeks earlier, I'd left my job for the second time so I was able to wall myself off from the world, and within days find my way here for the support, information, and guidance I needed based on member's experiences and results. Members also responded to my questions with links to online presentations and articles by leading experts in the field.
steveyp is among friends here, you are too. I welcome you to contact me privately if you'd like to talk about this more.