The following is a checklist to slow down CKD in cats:

I would recommend checking out these additional articles as well:
https://ckdcats.org/blog/Why-CKD-is-Common-in-Cats
https://ckdcats.org/blog/How-To-Help-Your-Cat-Feel-Better


Water - It is the most important element and plays a crucial role in flushing out toxins.  Make sure a CKD cat have at least 70ml water per kg(body weight) daily. A 4kg cat will require 280ml of water. Wet food contain around 75% Moisture.


Feed Wet Food - To increase water intake. 


Moderate Protein and Low Phosphorus Diet - To reduce the workload on the kidneys while still meeting the cat's nutritional needs.


AIM Supplement - Help do the kidney cleanup.
https://www.u-tokyo.ac.jp/focus/en/features/z1304_00039.html


Reduce Toxicity  - Supplement such as Astro Scrub, Activated Charcoal…etc


Phosphorus Binder - It is better to keep the Phosphorus level under <5.0 mg/dL / <1.6 mmol/L or at least <6.0 mg/dL / <1.9 mmol/L. Elevated levels of phosphorus can further damage the kidneys and contribute to other complications associated with CKD.


Fish oil and Q10 - Helps protect against many systemic inflammatory diseases. 


Balance Electrolytes - According to the regular blood work results, it will be determined if any mineral supplements are required.


Brushing Your Cat's Teeth - The buildup of plaque and tartar on teeth can harbor bacteria, which may enter the bloodstream through inflamed gums. Poor dental hygiene can contribute to the development and progression of CKD in cats.


Household and Human Products - Be aware of the ingredients of the products. Including chemicals for house cleaning and air freshener. Some plants or flower ingredients that are highly toxic to cats are used in cosmetic products, lotions, perfumes, hair products, etc. Additionally, toxic foods such as chocolate, coffee, and flower tea can be harmful if cats come into contact with them. Please remember to wipe your mouth before kissing them.