What you have done is remarkable, and apparently a short time. Two things, in my opinion are important to remember in addition to exercise and eating habits, and that is the overall trend of your eGFR and another test called Cystatin C. The trend is important because many CKD patients experience highs and lows as you have done. For me, I was at Stage 3A and gradually went to Stage 4 twice because of nephrologist recommended Torsemide and later Farxiga. This is individualized and not everybody may go through this. After 6 months or so, you develop a trend and that overall trend becomes important. Fortunately, my last two eGFR tests were 45 and 40. The second lab test you may wish to take is Cystatin C which I am told by my Mayo nephrologist is more accurate than a eGFR.