Button over featured image on hover

Using CSS, you can try just moving the ‘hover’ state a bit higher up the chain.

.brbl-blog-item:hover .brbl-overlay{
    /*Theme has this set to `transparent` so change to 70% white*/
    background: RGBA(255,255,255,0.7);
    z-index: 1;
}
.brbl-blog-item:hover .brbl-post-btn{
    opacity: 1;
    z-index: 10;
}

This does mean that the entire item including the content is subject to the hover, but most people will just hover over the image anyway. It’s a bigger target. This should give you the same effect but you can work on the level of opacity for the background colour and fine tune that as needed.