Server memory usage

I installed the 1.21.4 server plugin, and everything was working fine until I joined with the DH plugin. The memory usage started going up dramatically (I have 8GB of memory allocated) as well as CPU usage, then the server process got killed due to being out of memory. Is this an issue or do I need to allocate more memory/CPU?

I've also included a portion of the logs, if you need more let me know