This was released the other day: https://workspace.google.com/blog/product-announcements/create-on-brand-presentations-in-minutes-with-gemini-in-google-slides h

This was released the other day: https://workspace.google.com/blog/product-announcements/create-on-brand-presentations-in-minutes-with-gemini-in-google-slides https://workspace.google.com/blog/product-announcements/crea... So it should work for you now.