Where to add Unique Event ID to the new Google Tag?

In the documentation for deduplicating events it says “Open Universal Analytics tag inside the Web container → Click More settings → Custom Dimension → Add index and select Event ID variable.”

Link to the Documentation: How to set up Facebook event deduplication in GTM - Stape

Unfortunatly the Univerversal Analyitcs aswell as the GA4 Tag dont exist in Tag Manager anymore and are replaced by the new Google Tag.

How can I add the new UNIQUE Event ID to the new Google Tag?

Best regards