Write a plugin that monitors the maximum RAM usage, then determines the RAM limit that is closest to crashing the server, and if the server reaches that point — it automatically restarts the server. If the RAM usage is slightly lower — it silently removes mob clusters so players do not notice anything, etc. And send the actual file — most importantly, I FORBID YOU FROM WRITING EVEN 1 MESSAGE ABOUT CLEANUP, so players never see anything. Send a FULLY READY FILE. And instead of telling players that the server has a cleanup system, print everything only to the console so it is visible only there and nowhere else.