When a lot of things are running at once, hitting the open files limit on MacOS makes things start crashing. Running MacOS Server is supposed to help, but its configuration changes are inadequate if a lot of non-server activity is also going on. Every version of MacOS seems to have a different way of changing the open files limit. Here are some pages that try to follow the changes between versions.
It is not necessary to change the process limit to fix the open files limit. If System Integrity Protection is enabled, changing the open files limit requires restarting the computer.