Hi,
To turn off the sticky header, please add the below CSS code in additional CSS, Go to Dashboard >> Appearance >> Customize >> Additional CSS >> Paste the below CSS >> Publish it.
.sticky {
position: unset;
top: unset;
width: unset;
padding-bottom: unset !important;
background-color: unset!important;
}
If you need any other help related to the theme, do let us know.
Many Thanks