I have two suggestions for the auto afk kicking system.
1. In the console it should show who's afk and how long. Maybe it could be added in the player tab, next to the map name, something like this:
2. A op+ from my server said that he doesn't wanna be auto kicked for being afk, maybe if it's possible, you could change it so everyone that is op+ would not get auto kicked from the server.