Hello, Rafal
It is a normal situation that on page edit action you see a normal header which you also see on viewing the frontend page but on opening Theme Options it is different. This could be in case you have multiple headers which are loaded only for the live view page or edit that page by Elementor page builder. Once you open Theme Options default header is loaded with default options and to edit multiple one you should go to the Multiple Headers editor and there you will see the header which will be applied for the pages/posts conditions you set for it.
Please try Header Builder > Multiple headers > edit custom header for the Front page.
The blurred effect on your menu was caused by page’s custom CSS -> https://prnt.sc/q4aNmeR_p8LL . It was added to page XStore Custom CSS -> https://prnt.sc/lip507UD6qPb . We remove it for you so you may check now.
For better knowing what is wrong you may read how to use developer tools to inspect styles -> https://support.iterable.com/hc/en-us/articles/115001674223-Developer-tools-in-Chrome-and-Firefox
Best Regards,
8Themes Team