You have what is known as Stage 3 chronic kidney disease and this may have many causes of which kidney infection is just one. Others are obstruction to the flow of urine such as an enlarged prostate or stones in the renal tract.......others include high BP and diabetes.
In your case.....you had a urinary tract infection which needs to be investigated causing, i would suggest, your abnormal kidney function.
Certain drugs "may " have an effect on your kidneys, but if you need them to stay alive, then so be it.
The kidneys may never heal in that you will always have Stage 3 CKD (chronic kidney disease) but so what, 50 % of the population over 65 years of age, will have kidney damage.......you can live with that.
Do what the Drs tell you and give them some time to find out what caused your UTI...? prostate enlargement or kidney infection.