SharePoint Lists - Display one Choice selection in a Second Column Also.

I have two columns in a SharePoint List. Let’s call the Column 1 and Column 2. They are both Choice Columns. They also both share two common choices, Completed and Cancelled. If someone selects one of those choices in either column, I would like it to be automatically displayed in the other column also. Meaning, both columns should match if Completed or Cancelled are selected in either column. If another choice is selected in either column, the other column should remain empty, for a manual selection of one of the other choices. What would the JSON code be to do something like this? I want to keep all my other formatting intact, just looking for the IF statement to sync the text between the two columns, no matter which is changed.