Resizing the ad container while having it on display none will return offset width and height of 0, which will cause ads not to play when ad sizes are set within the clients DSP. Also making sure that the inner containers of the ad container are full size. The container is now hidden/ displayed using z-index.

src/sass/plugins/ads.scss

@@ -9,7 +9,19 @@
     position: absolute;
     right: 0;
     top: 0;
-    z-index: 3; // Above the controls
+    z-index: -1; // Hide it.
+
+    // Make sure the inner container is big enough for the ad creative.
+    > div {
+        position: absolute;
+        width: 100%;
+        height: 100%;
+        iframe {
+            position: absolute;
+            width: 100%;
+            height: 100%;
+        }
+    }
 
     &::after {
         background: rgba($plyr-color-gunmetal, 0.8);