How to Create a Custom SEO-Friendly URL for the Gridbox Checkout Page

Hello,
I am using Joomla 5 and Gridbox Store.

The checkout page is accessible only through the following URL:
https://www.site.org/component/gridbox/checkout-ua?Itemid=0&lang=ua

I would like to use a clean SEO-friendly URL instead, such as:
https://www.site.org/checkout

However, I cannot find a corresponding menu item or page in Joomla Menu Manager or Gridbox Pages that would allow me to assign an alias.

Could you please advise how to create a custom SEO URL (alias) for the Gridbox checkout page?

Thank you.