Hello,
1/ The issue was caused by your custom css -> https://prnt.sc/gzxo39pHrMGj (added from Customizer -> Additional CSS)
You may add next custom css and keep that CSS on you web-site ->
.et_b_header-widget {
position: relative;
z-index: 3;
}
1.2/ To fix the issue in sticky header you should remove your custom CSS -> https://prnt.sc/PJtwHI4Ps8PO – there cannot be fix that will help in your case of sticky-header custom styles added
Regards