Hello,

01. Please deactivate all the 3rd party plugins and activate only theme-required plugins on the site and then check the issue. Then Activate the 3rd party plugins one by one and check which plugin is creating the issue for you. Otherwise, if the issue still exists then keep the 3rd party plugins deactivated and convert the images into webp format and let me know I will check and give you a possible solution.

02. I have checked your site and the header is showing fine in the “Barista” Category menu.
Screenshot for clarification:
https://ibb.co/dWMfrqr

Check back your site after completely clearing the browser cache and check the issue.

Best Regards.