Change shortcut for switching to the next most recently used app among your open apps in MacOS
Not sure if this is what you wanted, but here's a possible solution without using any third party apps:


Go to System Preferences > Keyboard
Click on Modifier Keys... (Refer to screenshot)
Map Option to Command, and Command to Option (or use the modifier keys in any way you want)


Now you can use Command key shortcuts using the Option key.