5.9 to 5.7 in 4 Months

I got bloodwork done for the first time since getting my 5.9 A1C results near the end of last year, and now I am at a 5.7 A1C. Any thoughts on how to process this? Seems good, like I have done some things that are working. Does it get incrementally harder to lower the lower you go?

I have changed so many things. Way fewer carbs and processed foods. More protein, fat, and fresh fruit and veggies. Mostly stopped eating within a couple of hours before bed. I rarely eat carbs by themselves when I do eat them (usually they follow protein, fiber, and fat). I learned that my blood sugar spikes more in the middle of the day, so I especially limit carbs then. I am drinking more water. I was already slim (male, 6ft, 143 lbs), so instead of losing weight I put on nearly ten pounds through strength training.

I would like to get down to 5.5 or so and then maintain. I am happy to hear advice, anecdotes, etc.