Hi there!
Thanks for your query.
There is no default way to do that. But if your menu items doesn't have any active links then you can try custom css.
Please use the following code in your custom CSS:
body.ltr .offcanvas-menu .offcanvas-inner ul.menu > li.menu-parent > .nav-header > .menu-toggler {
width: 100%;
text-align: right;
}
Note: Path towards custom CSS(Joomla 3): Extensions>Templates>Styles> Click on your current default template name then choose Template Options. Then find custom CSS within the custom code.
Hope this helps!
Best Regards