Challenges force only certain plays, interfering with the flow of games felt by the player and causing stress.
Challenges are turning games to be enjoyed into harsh labor.
So, as written in the title, it should be very simplified so that it does not interfere with game play.
Remove all the detailed challenges, leave only kills, head shots, and melee attacks, and put only the detailed challenges in the ultimate challenge, but easy enough for anyone to achieve.
The event challenge only needs to be conditioned in a specific game mode.