How to select the current account in an Android application with Youtube API?

Question

Google

Our Android app interacts with Youtube API v3 and users have complained that it is not possible to select a current account, since authorization is performed by mail address (via Android account) via OAuth 2 and access is provided only to the main (non-branded) account, and many there are several users of such accounts (several brand accounts have been created for the main account). We did not implement such functionality, because at the time of development this Youtube opportunity to select an active account was missed. As I understand it, brand accounts are additional accounts that are linked to the main account through which they are managed. Each brand account can have its own separate channel on Youtube and in general, a similar account in the Google environment is presented as a separate user,
On the Youtube site itself and in their Android application, it is possible to select the current active account. In Andorid Yotube API, there is no such choice when authorizing. I found information on the net that authorization using the Web has the ability to select an account, and therefore Android had a method of authorization through WebView, but this method for Android is no longer working. Therefore, there is a question - how to get a list of user brand accounts in Android and subsequently organize authorization in the Youtube API for the selected account? In general, you need the same account selection window in the Youtube application, followed by the possibility of obtaining the data of the selected account, etc.