⚠️ Controller accounts are deprecated. Your Stash account should be its’ Controller.
First, connect your account to the Staking dashboard.
Either from the "Overview" tab or "Nominate," you'll be welcomed with a warning announcing the deprecation of the controller accounts. Click on "Update Controller to Stash."
A new screen will appear where you'll see how the controller account would be updated from your current controller (1) to your stash (2) account.
That's it! You have now updated your controller account to your stash!
If you don't want to use your stash account often, you can create a staking proxy which can do all staking actions on its behalf. It has the same advantages as the controller, but even more flexibility. Learn more here.