1.14 Server Lag

Hey there,

I’m currently running a server on version git-Paper-178 (MC: 1.14.4) and im experiencing some TPS lag.

We’ve been looking for the problem for quite a while now. And the only thing that changed was the server version. Before we updated we ran on version spigot 1.8.8.
In the first place, We blamed our internet speed for the TPS loss and setbacks. But In the past, we hosted a server (also 1.8.8 and before) with 60+ plugins and around 10 players without any lag. Soon we’re upgrading our Internet speed to 500/500mbits so that should not be a problem anymore. If that was the case.
So to clarify my question; What exactly Is causing the TPS loss and/or any sort of lag.

Here is our timings report:
https://timings.aikar.co/?id=80c9708fcb09417f9db3385200cdaf06

The specs of our server are:
CPU - Intel® Ceon® E5504 @ 2.00GHz
Ram - 24 GB
64 bits OS

These are our startup commands:
@echo off
java -Xms12G -Xmx12G -XX:+UseG1GC -XX:+UnlockExperimentalVMOptions -XX:MaxGCPauseMillis=100 -XX:+DisableExplicitGC -XX:TargetSurvivorRatio=90 -XX:G1NewSizePercent=50 -XX:G1MaxNewSizePercent=80 -XX:G1MixedGCLiveThresholdPercent=35 -XX:+AlwaysPreTouch -XX:+ParallelRefProcEnabled -Dusing.aikars.flags=mcflags.emc.gs -jar paper-1.14.4.jar
pause

Looks like the GriefPreventionDynmap plugin is causing lagg. Also the pillager and villager entities have a huge performance impact which is a known problem in 1.14.