- Using an AD group. We can't create an AD group because these 400 users is just a subset of the large of number users. We have a soft-launch with a small selected array of people. Creating an AD group for this purpose does not make sense, especially because of bureaucratic delays it will cost us.
In SharePoint, I could easily add a lot of users in one go by typing all emails with a semicolon separator, but that trick is not available in PowerApps, it seems.