Sorry for facing this issue, it's my pleasure to help us.
Welcome to the Shopify community!
and Thanks for your Good question.
can you please share further issue screenshot?
This is an accepted solution.
Hi, are you referring specifically to the header navigation menu?
If yes, please try removing a few links/items from the navigation menu and recheck if the issue persists. Sometimes, the mobile navigation menu (with the hamburger) is shown on the desktop if there are too many items.