When Should I Get Retested To See If EGFR Level Goes Up?

Question : Hello. I am a 30 year old male. I have questions on my most recent labs, and my egfr levels since 2019 to now. I tested positive for sjogren”s and have seen many doctors which is why I have gotten allot of bloodwork done. I am attaching my most recent labs and my EGFR, creatinine and potassium levels since 2019.

- Is EGFR supposed to fluctuate allot? Mine has fluctuated allot.

-My EGFR is the lowest it’s ever been. Potassium/ Creatinine have risen slightly and are on the high end on scale. Could this mean possible kidney disease?

-What is the lowest EGFR a 30 year old male could have without cause for concern? I feel like 97 is low especially for my age.

-When should I get retested to see if EGFR level goes up?

-I drink muscle milk protein shakes daily (32 grams/day) to help me get my daily protein intake for about a year. I am 5”11, 210 lbs. Could this be harming my kidneys?

-In attached labs, my ph is the highest it’s ever been. How can I bring this down? And could it be related to possible kidney issues?

-I tested positive for calcium oxalate crystals in urine. Does this mean kidney stones?
Will drinking more water help me get rid of them?
What foods should I avoid?

I workout, drink at least 3liters of water/day, and for the most part eat a pretty clean diet. I also take take turmeric, fish oil, multi, b12, vit D daily. So I am a little perplexed at my lowering EGFR numbers. I hope you can clarify my questions. Thank you.