Add Ui Dynamic forms to Custom Variables module

I want to add UI dynamic rows for Custom Variables module.
https://devdocs.magento.com/guides/v2.4/ui_comp_guide/components/ui-dynamicrows.html

You can see here: magento-site.com/admin/admin/system_variable/new

But it doesn’t have xml layouts.

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Maybe someone could help me. How can I add dynamic rows for that module?

Example
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