Pass on some of the customers money
You need to create the div text block outside of the flex/grid, you are putting the text block inside the flex/grid which is of course just going to create a new column.
Go to the footer and add a schema, which allows the person to edit it via the customizer
here is a great youtube video he shows you how to create a new section and add the changeable elements to the customizer, use the knowledge and apply it on the element you create in the footer
You will need to understand HTML. Look at the footer find the section and place it outside of the flex/grid whatever they use to make the columns