The latest innovation in the Teams client is the display of a P marker to the upper right of the user profile photo (avatar). This means that the client runs public preview software and the marker is intended to allow users and support personal understand when clients run public preview rather than the generally available software. Of course, users only know this when they’re told about the magic P.
Like all applications, the Microsoft Teams client has some “hot” files that the app depends on. Antivirus software processing can affect app performance if it conflicts with the hot files. You can exclude the Teams hot files from antivirus processing to see if that helps performance. Like anything to do with antivirus software, it’s a question of balancing security and performance.