I installed this because i got chunk lags and it fixed that. Now i am getting huge garbage collector lag spikes and i have no idea why

This is not the place to ask for unrelated server performance help. I recommend asking in the Paper Discord (if you're using Paper) or in another hosting / server discussion forum instead for your particular setup.

If your question is specifically about Chunky, feel free to join our Discord server and ask in the the support channel.

If you have a bug to report, you can open another issue here on Github with relevant details and reproduction steps. Keep in mind that memory / garbage collector issues usually have to do with your hardware or server configuration and are usually not reportable bugs.