Bedrock offhand

In Minecraft on bedrock instead of have a button for both the crafting menu and the inventory, because they are the same thing make it so one of them uses the offhand, or make it so you can set up a button to be the offhand or make it so the use button like for eating or placing used the offhand or make it so when you crouch and press the use( place/eat) it uses the offhand, and if you do make it so there is a way to put something into the offhand without going into the inventory, like by crouching and dropping it or something