An Engaged session is one that lasts longer than 10 seconds, has a conversion event, or has at least two page views or screen views.
Here is Engaged Sessions in GA4 Screenshot
Here is Traffic acquisition Engaged sessions in GA4 Screenshot
Here is Engaged Sessions Traffic Type GA 4
Here is Engaged Sessions Per User Ga 4
Engaged Sessions Per User Ga 4 is calculated by dividing the total number of sessions in a given time period by the number of users in the same time period.