Chronic Kidney Failure - what stage?

Back in 2021, our male cat suffered three urinary blockages in a month. After the third one, he had PU surgery. He's been in good health ever since but his creatinine levels since then have always been around 2.0 - 2.3. The vet said he may have suffered an acute kidney injury during those blockages and his creatinine may ever return to normal. He also said it was possible one kidney was permananetly injured but the other one may be completely normal.

He's now 9 years old.

I took him for his check up and his creatinine level was up to 3.1. The vet declared him in Stage 3 kidney failure. He looks great, coat is beautiful, is a very healthy weight, and everything about him seems normal. His SDMA has never been higher than 14.

I took him for repeat blood work last fall and creatinine had come down to 2.7. Most of his bloodwork was normal, except Potassium which was 3.5. Phosphorus was 3.1.

Hi urine specific gravity was 1.021.

Urine Creatinine 111.3 mg/dL

Urine Protein 35.4 mg/dL

Urine Protein/Creatinine Ratio - 0.3

I'm confused what stage he is and whether his values were caused by acute kidney injury when he blocked or it's Chronic Kidney Disease and his kidney(s) are failing and will continue to fail. And if he has CKD, what stage is he? When I look at Iris guidelines, it refers to Creatinine and SDMA and those two put him at two different stages.

The vet recommended putting him on prescription food for kidney failure, but he doesn't like it and won't eat it.

He was on a Urinary diet, but she said to stop that. He's been eating Fussiecat wet food for now and seems fine.

Not sure how to proceed with him. I obviously want him to have best quality of life as long as possible.