Cold hands have ruined many a hunt for me. Seems like no matter what you try–after about the one hour mark the fingers begin to get numb. This goes double when you want to work in the water. The solution below took me decades to work out–and is pretty solid. First you need some very thin liners. These ca be wool or fleece. They need to be very thin so as not to compress your fingers inside the other two layers. The second layer is Nitrile shoulder gloves. These can be gotten at a safety supply company and act to keep the arms of any heavy jacket you are wearing dry.
The third outer layer is what gives you the real protection from cold–“Bare” 7mm.Neoprene mits with Velcro closures. https://www.baresports.com/products/accessories/gloves/7mm-3-finger-mitt/ These are a great product and can be worn by themselves in quite cold temperatures. However if you are not in full Neoprene and want to keep your arms dry–this three layer set up is the way to go. I’ve tested this system in below zero conditions and it works really well. If you chose to work shallow water in cold conditions wearing waders always have a belt around your middle and be careful that there are no holes gouged out by ice at the water’s edge.