My question is how can I keep the disease from progressing?
The best diet to help treat both can clash but the kidney issue is your more present issue so I would defer to your nephrologist
There is a diabetes drug on the market that has shown good effect in both blood sugar control and slowing down/halting kidney disease, minimally delaying the need for dialysis for some number of years
The actual drug is Dapagliflozan which is sold under the brand names Farxiga, Forxiga and Edistride and perhaps worth a discussion with your Doc or Endo or Nephrologist
And, get wicked good control of your blood sugar - anytime your BG is higher than 157 you are doing further damage to your already compromised kidneys - so whatever you have to do it's time to get doing it