Two Functions Conflict

There is a problem when you try to use the function listed here:
https://www.billerickson.net/code/add-column-classes-to-display-posts-shortcodes/

and the function listed here:
https://www.billerickson.net/code/add-read-more-to-display-posts-shortcode/

Basically because the “Read More” code hardcodes the class for the $output string, it overrides the function that adds the column classes. I’ve tried playing with different code, but can’t seem to resolve the problem. Can you please post “Read More” code that utilizes a variable for the class, so it can be used in conjunction with the Column Classes code. Thanks.

https://www.ads-software.com/extend/plugins/display-posts-shortcode/