It is possible to enable an attendee report in Microsoft Teams via policy. The following PowerShell can be used with the Skype for Business Onine Windows PowerShell Module installed:

Import-Module SkypeOnlineConnector
$sfbSession = New-CsOnlineSession
Import-PSSession $sfbSession

# Allow attendee list download during meeting
Set-CSTeamsMeetingPolicy -Identity Global -AllowEngagementReport "Enabled"

This give the organiser an option to download an attendee report showing when users join and leave the meeting (but currently only available to run during the meeting).