Purchase order approval Notification is not allowing to add new fields to the template

Hi Team,

We have a requirement from business to update the PO Notification, and it should display few additional fields like Business unit and DFF fields.

We have customized the Purchase order Notification Data model, but the changes are not reflecting in the notification when we add new fields to the template.

Any insights or any experience with this customization.

Thank you,
Kalyan