Benign Cysts-CKD 4

Hello,
When my spouse was diagnosed with CKD it was shared that he had two benign cysts in his right kidney. One that was 5.3 x 4.6 x 4.1 cm and one that was 1.3 x 1 x 1.5 cm.
I had asked his Nephrologist at that if that was a contributing factor and have asked a few more times, and they said "No". and said that they they were not an issue.
He has declined from stage 3 to stage 4 what I feel is a short amount of time. Within in year.
He has stage 2 Diabetes and High Blood Pressure, which has been in control especially within that time frame.
I am thinking of finding another doctor and getting a second opinion about the cysts.
My long story/background is to ask, has anyone have benign cysts and what did your doctors do about them?
**They never biopsied his kidneys, the doctors say that his CKD is likely due to early uncontrolled diabetes.
Thank you.