If there are more posts then the button should look like the one on the proof, No border-radius, Blue background, white text, etc. like the other buttons on the site/proof. If there are no posts, there is a class that is added to the <button> that is selected in the third snip called "done" (circled in red) that corresponds to some css for that class, just make display:none, so that nothing shows up. No use in having a button that does nothing. Thanks. Not sure if you can edit the plugin css or need to write a class in one of the css/scss files to hijack it.
Dev vs Proof vs Load More inactive button