Hi,

01. The HTML Blocks for the Mega Menus don’t work for the Mobile. You need to create a separate Menu under the Dashboard > Appearance > Menus with simple classic style (i.e. Parent item > Sub item > Sub item) and then set that menu for the Mobile under the Header Builder.

Further, you can read these Menu related guides of the Theme Documentation:
https://xtemos.com/docs-topic/create-mega-menu/
https://xtemos.com/docs-topic/adding-menu-to-the-site/

02. Please try adding the following Custom CSS in the Custom CSS for Mobile area under Theme Settings >> Custom CSS.

.wd-header-cart .wd-tools-icon.wd-icon-alt:before {
    content: "\f105";
    font-family: "woodmart-font";
}

Best Regards.