Summary
To change how links open from Outlook and Teams you need to change this setting in the application.
Outlook settings: File > Options > Advanced > File and browser preferences.
Teams settings: Settings > Files and links > Link open preference.
Body
Microsoft has made a recent update around Aug 2023, which affects the way links in Outlook and Teams are opened within these applications. Previously, the default browser setting determined how links were opened, but now they are controlled within the individual applications, with the default set to Edge.
To change how links open from Outlook and Teams you need to change this setting in the application.
- Outlook settings: File > Options > Advanced > File and browser preferences.
- Teams settings: Settings > Files and links > Link open preference.
More info here:
Microsoft - Web links from Outlook and Teams open in Microsoft Edge in side-by-side view
Microsoft - Web links from Outlook emails and Teams chats open in Microsoft Edge