As repeatedly said already, a life jacket is a must. I'm so use to wearing mine as I hunted from a kayak for many years, had no problem shooting with it on either. You're just flat out stupid if you don't wear one and it's the law, just sayin'.
I have 5mm neoprene waders and i've been in the drink with them in January with a PFD on and slipped off a shelf walking from shore without one once. In both cases, I floated, it's unlikely you will sink with neoprene waders as they are very buoyant.
If I go out alone, my wife always knows where I'm hunting and I have a gps app on the phone that she can see and I check in throughout the hunt.
Even with a PFD, waders and your location known, nothing will prevent exposure to the elements if you take a dunk. Sometimes it's best to just stay home and clean the shotgun. No duck is worth meeting God any earlier than is needed.