We are considering testing with TestFlight.
As an external tester, tests can be conducted with a maximum of 10,000 users, but this is a question about how to add users when many users test.

For example, if I want 1000 users to test, I think that it is necessary to add user information for 1000 users in iTunes Connect.

In such a case, for example, create a mailing list and register the email address as an external tester.
Is it possible to notify everyone on the mailing list and get a test flight?

If a test flight is launched from the link in the invitation email, should it be associated with the device's appleID? So I think there should be no problem with the use of Mailis, but I would like to ask if you have any advice.