There's an open-source Chrome extension (also works for Chrome OS) to show Notification Badges for MS Teams PWA (Progressive Web Apps):

https://github.com/devoldoak/msteams-notification-badges

For notifications, the Administrator needs to enable the NotificationsAllowedForURLs policy, which automatically allows notifications for Teams on the web:

https://learn.microsoft.com/en-us/microsoftteams/teams-progr...