I think bone broth will be okay. It is better than no fluids at all.
I do not have thorough experience with kidney failure. But my own dog was diagnosed with elevated BUN and creatinine some years ago now (2011). She was considered in the very early stages of kidney failure.
Her blood Phosphorus however wasn't elevated.
Her only symptoms were drinking more water, and peeing in the bed (very unusual for her)
Our vet immediately put her on a kidney diet (prescription diet) plus ACE inhibitors. That had remarkably good results with her and soon her elevated blood values were back to mid-normal.
However, I have no idea how long that positive effect would have lasted, as she only lived another 6 months after that, passing from something totally unrelated -Hemangiosarcoma of the spleen.
But even weeks before her diagnosis of Hemangiosacrcoma, all her blood results (re: renal problems) were all reading 'normal'.
But her kidney problems were very 'early-stage' when we caught them.
So it might be a whole different story with your dog.
You really need some good advice regarding protein intake and diet, and this is quite complicated if you are considering home cooking for her. You will need advice.
I advise you to 'google' "Home cooking for dogs with renal failure" and there will be many results.
Otherwise, a prescription diet may help.
My dog had that, and was allowed some scrambled egg or boiled chicken breast occasionally.
In late stages of renal failure they completely lose appetite and feel nauseous almost constantly.
I really think you need your vet's advice. But not all vets are good with nutrition.
There is a community here about dogs with renal failure. There will be good advice there and suggestions etc. When I find it I shall post it for you.