Hi there!

Thanks for your query.

I have a suggestion for you.

If your menu headers do not have any link to follow then the following code snippet in your custom CSS will do the job done for you:

.offcanvas-menu .offcanvas-inner ul.menu>li.menu-parent .menu-toggler {
    width: 100%;
    text-align: right;
}

Note: Path towards custom CSS: Extensions>Templates>Styles> Click on your current default template name then choose Template Options. Then find custom CSS within the custom code.

Best Regards