Don't know how much you use your keyboard or mouse but I dont think rechargeable batteries make sense. I am using normal Duracell in my keyboard mouse combo and haven't changed them for 1.5 years.
I had a similar problem in Mi 11t pro. Found the solution online to let the phone discharged completely and then charge to 100% while being switched off. This just calibrated the battery and then phone started getting charged to 100% normally
I am using cold pressed Sunflower, Safflower and Groundnut oil since almost 3 years and can say it is really good for health. It's bit costly but cheaper then medicine.