Not talking about full sleepers like Rust, but if someone logs out without doing the proper prep they will be unconscious in world for some significant amount of time (like a few hours, not 30 seconds). Add a log off option to your bound location so you can safely exit the world if you want to log off there, an possible an alternative where you crate a campfire and use a bedroll to log out (would be complicated and time consuming enough to not be usable in combat but would also let you to log off away from home).

I think this would 100% solve combat logging and would be pretty interesting, without really inconveniencing anyone.