Building emails with personalized dynamic data from any data source is not possible until the upcoming 2021 wave 1 that is planned in April. Read more about the new release.
Personalizing emails is very essential for marketing emails to be effective, it is not showing first and last name in the email. It should reflect the areas of interest to the client and solutions that serve those areas.
Current dynamic content limitation
The main limitation currently with the content assist is having all the data around the contact record. Read more about the dynamic content assist.
The dynamic data is pulled directly from the contact record or from another table that has a direct relationship with the contact record, which limit the dynamics content.
All tables related to the contact table have to sync with data sets. Read more about syncing the tables.
2021 Wave 1
Soon in April, Dynamics 365 Marketing users will be able to include dynamic content from any data source that is not contact related.