A1C

When it comes to diet A1C will aways go lower when carbs of any kind are reduced and how much you reduce them is up to you and if your diet consists of mostly processed foods then switching some of that up with whole foods will also lower your A1C but probably not as much and it'll take much longer. When carbs are removed there is no spike or almost no spike which results in less insulin produced so blood sugar has not option but to go lower, it's just basic biology.

Of course there's other lifestyle factors that effect A1C. Losing weight, exercise, proper sleep, stress management, properly hydrated etc and of course medication. Personally I had other health issues and an A1C of 5.9 and after mucking around for over a year I decides for low carb and a ketogenic diet and my A1C fluctuates now between 4.4 and 4.9 most of the time and I also exercise regularly, my weight is in a normal range and I'm 71. I'm sure you'll figure out what you need to do but this is just my opinion and good luck.