@Geez This would be used to join a friend in game through their Steam profile.

In T163596#2285766, @Geez wrote:

Hello AlexAnimateMp4.
Is your goal to just connect to a specific community server through command or is the goal to join onto a server your friend is playing (without possibly knowing the exact server?).
The second is probably not possible but the first we could help with, as there is a direct connect parameter that can be added to your executable or as a launcher command.
Regards,
Geez