Thank you so much for using the support forum for the query.
There is no any option to add your own custom link for the secondary button. If you need your own link, you need to customize the theme code. If you are familiar with theme codes, please customize it, otherwise please contact us via email, we will help to customize it.
Note: Child theme is recommended to customize theme code. https://www.templatesell.com/blog/child-themes-and-its-usage/
Let us know if you have any further queries.