Just use Erythritol and Monk fruit 0 cal sweetener. No potassium, no sugar, 15 mg of sodium. Use 1 to 1 as sugar replacement. Available at Costco in dry form and available at Amazon as a liquid.

Rhubarbs contain nearly twice as much oxalates than spinach, excess oxalates cause kidney stones.
I like to share my experience during the kidney donor eval phase. My wife the donor during the evaluation was found to have kidney stones and at one point I felt i was very near to the transplant phase ...but still very far from reality ! I must thank the Kidney donor Dr who identified the issue and told my wife to stop taking calcium supplements which worked but it took 2 months but it came through... you can understand what was going on in my mind for those 2 months.
For anyone has been identified with CKD... they should try avoid rhubarb & spinach. Also both spinach & rhubarb contain a lot of vitamin A which helps to clot the blood... so in my view all CKD people should exercise restrain.

@colleenyoung I’ve been away from Mayo Clinic Connect lately because I’ve had company. My experience with rhubarb is mostly wishing I had some growing in my yard! When I find it I’ve made a simple sauce to spoon over other goodies or a crisp, crumble, Brown Betty, etc. I use an apple recipe and substitute rhubarb for the apples. I am diabetic so I am very concerned about the carbs in all the sugar required in these recipes. But I have NEVER had good results cooking (especially baking) using any sugar substitute. I just make the real deal, stick to very small portions, limit the frequency of those portions and share the end result with other people so I don’t eat too much myself. I never considered this stuff to be a CKD concern at all. Diabetes concerns more than make up for using caution with rhubarb!