Starting with ONTAP 9.7 the following is true:
Whenever an external or onboard key manager is configured, new aggregates will have NetApp Aggregate Encryption (NAE) enabled by default. New volumes that are not part of an NAE aggregate will have NetApp Volume Encryption (NVE) enabled by default.
NetApp offers two forms of hardware encryption NetApp Storage Encryption (NSE) and NVMe SEDs. For systems using NSE the default NAE/NVE encryption will not occur. However, for NVMe SEDs the default NAE/NVE encryption will occur.