Hello @michigancreative,
Thanks for writing in!
What you have in mind is not the way the Post Navigation element works. Be advised that this element is just using the default WordPress post navigation turn into an element for the builder. The post navigation is using the posts_nav_link() (https://developer.wordpress.org/reference/functions/posts_nav_link/) which displays the post pages link navigation for previous and next pages. When you reach the very first post or last post, you will always have one link. The post navigation will not loop to the very end or start of the items.
What you have in mind, the looping of the post navigation items could be possible with custom development, but this would be outside the scope of support we can offer. You may wish to consult a developer to assist you with this.
Please note that custom coding is outside the scope of our support. Issues that might arise from the use of custom code and further enhancements should be directed to a third-party developer.
Thanks for understanding. Take care!