Once support for Windows 10 native notifications is released, users who choose to use Windows notifications will be able to utilize Windows OS specific settings for the length of time to display notifications. Mac does not have an OS specific setting, so will not have the support.
As the last status states, we have been testing for several months. Although many people have asked for this feature, we received a similar amount of feedback from other users that they prefer the Teams notifications and don’t want them changed. We are currently testing a feature for users to choose between Teams notifications & Windows notifications.
We will update you as work progresses.