Data Manager's capabilities for importing large data

Summary:

Data Manager's capabilities for importing large data into an App that has inter-related Business Objects.

Content (required):

We are currently in the process of creating an app using Visual Builder, and one of our requirements involves importing a significant amount of data. During my exploration, I discovered Data Manager and its ability to import data using CSV files. I would like to gather insights and information on several key features of Data Manager related to our data import needs:

1. Performance: How efficiently does Data Manager handle the loading of large volumes of records through CSV files?
2. Validation: Does Data Manager validate whether reference data exists in the tables before successfully creating or updating a data row in an object? For example, does it check if an employee's department exists in the department object?