Uninstalling an Un-Modded OS is fairly simple. Here are the steps for Ubuntu but you can do them for the distro you're using.
Make sure you're not inside the distro. You will need to run this in a Termux shell.
Go to the app and select the distro you're using. You'll an uninstall button beside the Install button
Just press the Uninstall button and paste the copied code in Termux and execute it with your enter key.
Boom! 🔥 that's it!