An error occurred while saving the commentEggbert commented
Many social communication tools already have this functionality.
Discord for example allows you to set a default nickname and also allows you to create a custom nickname for each channel you join.
Skype has always had this ability.
Not sure how this was overlooked in Teams. If I were joining a channel about programming I might want to use "Bob C#" to indicate that I preferred to be called Bob instead of Robert and that I specifically code in C#.
This feature remains under review.