While running a server (8gb ram), I ran into a plethora of tickrate issues and general "lag" when running ProbablyChests & Naturalist.

Removing them from the server mods, and disabling them by extension, reduces the memory usage of the server by several gigabytes.

I highly suggest removing them both from your mod list, or from the pack entirely, and finding potential replacements.

Spark profiler showed upwards of 10-15% server resource utilization with the two mods (each contributing about half), with spikes when mobs added by the mods moved. Extreme lag would occur when mimics were triggered for the first time.