Hello and welcome to the forums
Can I ask where you are located as others in your location may be able to advise on handling the medical costs. (New Zealand may be twenty years behind the times in terms of medicine but I am very grateful for a public health system).
Not sure I'd care about the spikes if I were that underweight. Spikes are a long term issue. And if your issues are caused by a honeymoon that should theoretically pass in time? Are you testing for ketones?
Forum rules don't allow us to diagnose so I have to be careful what I say. But if you think you are in honeymoon have you tried tiny doses of insulin (get a half unit pen)?
And many of the T2s on here maintain there weight on keto diets because they can't tolerate carbs. What happens if you pack in the fats and proteins?
Another thought, did your issues happen after covid? There are some strange reports about covid induced (sometimes temporary) diabetes that have been cropping up.
And one final thought, how confident are you that the weight loss is caused by diabetes rather than some other issue? (Disclaimer, I am not a doctor so I am just throwing out some suggestions).
Good luck.