Hello Kevin,
To reduce the opacity, add the given CSS into your Customizer >> Additional CSS.

.ht-slide-overlay {
background: rgba(0,0,0,0.4);
}
#facility-content-section .overlay {
background-color: rgba(20,20,18,0.3);
}
#ht-callus-section .overlay {
opacity: 0.2;
}
#ht-colophon .overlay {
background-color: rgba(0,0,0,0.4);
}

Thank you.