Its just a shot in the blue, but try and slap that whole minecraft Server into a VM with 4 (real) cores and as much ram as ONE Node has. Turn on NUMA. Install Openjdk-8-jre-headless.
Create a runfile with:
and Paste in the following:
java -server -Xms6G -Xmx6G -jar nameofjavafile.jar nogui
6G is the Amount of RAM Java will use, and it will preallocate it. Save and exit
chmod +x Launch.sh
run it with
screen bash Launch.sh
so it can run in the Background, without the need to have the SSH Session open all the time.
Other Solution is: More Singlecorespeed = more better.
Minecraft, especially Java, is just a Performance Nightmare. It got better in 1.16, but not that even a 5950x can handle more than 100 People at once.
Best Performance is in my opinion on Paper, but there u got no Modsupport if i remember correctly. One thing to note: if the VM crashes for whatever reason and Paper gets a “forced shutdown”, it will most likely corrupt your world. Dont ask why i know that.