Assuming that you have chosen not to go the subcutaneous fluids route?
Totally get that.
I had a lovely rescue cat, Maud (my user name) who developed chronic renal failure in her later years.
Vet recommended fluids, and I resisted mightily.
No needles, no.
Well, I went for it eventually.
My cat was a good candidate, very calm.
I gave her fluids for the last year of her life, her 20th.
It didn’t extend her life, but I believe it made her last year more comfortable.
She succumbed to her “other afflictions,” as her vet said.
Dispensing fluids isn’t for everyone, and it isn’t a cure, but, end of the day, I was glad that I did it.
Peace.