Explanation
To use Data Loader to mass import new records to a custom object from a new API, the administrator will need to append their security token at the end of their password to login. The security token is an alphanumeric code that is required for API access when logging in from an IP address that is not trusted by Salesforce. The security token can be obtained from the user's personal settings or by resetting it via email. Adding a permission set, resetting the password and the security token, or using the Data Import Tool are not necessary for using Data Loader. References: https://help.salesforce.com/s/articleView?id=sf.data_loader.htm&type=5
https://help.salesforce.com/s/articleView?id=sf.security_token.htm&type=5