I tried looking at the page again. It seems the issue is not with the lightbox displaying over the flyout.
The form inputs itself are disabled/not active for somereason.
I tried resizing the lightbox area but still form inside the widget is not clickable.
It is because some plugin/lightbox/theme is disabling all forms when lightbox is open. After closing it is accessible. This is something which you can check on your side.
There is not issue with UFW as you can see the “text” is selectable. It means that UFW is on the top and accessible. Only the form is disabled is not clickable.
Can you please check with the theme/lightbox author to see if they can find it out ?