I like idea of using one wallet for both hot and cold storage with separate codes for each.
I hope you understood what you wrote and expressed your idea correctly through writing because this sentence is non sense.
Hot wallet and cold wallet are different like you shared your thinking in other sentences but what does it mean in this sentence?
"Using one wallet for both hot and cold storage with separate codes for each", what?
One wallet with separate code?
One wallet for both hot and cold wallet?