Hi. Using standard Sydney theme- google webmaster tools tells me the site has a high cumulative layoutshift.
I’ve disabled the preloader (display none) to see what was going on.
You can see in the movie at https://drive.google.com/file/d/1E6cJL8le6vPa8h2Fqgbo_1jiF9YgkPAk/view?usp=sharing
THe body is higher, then the menu appears, then the body is pushed down,
This happens with both sticky and static menu.