Sytax formula for date (6 days before)

Hi All

I have a scenario in which we would like an Action button to appear 6 days before a date field in a related module and after the date has passed

For example

The date is set to = 1/10/2023

We would like the action button to appear from - 25/09/2023 and after 1/10/23

Working with good old ChatGPT I have managed to create this formula, Sugar saves it, but it is not working

isBefore(related($Accounts, "delivery_date"), addDays(today(), -6))

Any help and suggestions would be greatly appreciated

Thanks again