When using the Microsoft Teams machie-wide installer, the Autostart option for Teams can either be enabled or disabled for all users of the machine.
There is no way for the user to change the autostart behaviour within the Teams client.
Especially in multi-user environments like Citrix VirtualApps + Windows Server 2019 this is problematic because the users cannot set the autostart option to their individual liking.
In per-user installation mode of Microsoft Teams the user can change the autostart option. The machine-wide installation should also offer this option.