I noticed recently that when OMV 5 on my Raspberry Pi 4B is connected to my network via 1Gbps ethernet, the game Elite Dangerous on PC freezes for almost one minute at a little more than one minute intervals, rendering the game unplayable. I also noted that if the RPi is connected via 2.4 GHz Wi-Fi, the game nearly doesn't freeze (once every hour for a few seconds?). I cound't connect via 5GHz Wi-Fi because OMV for some reason is not able to create or change the wlan connection; both the web interface and omv-firstaid reports error messages.
When the RPi is only running Raspbian, the game runs normally, no matter what kind of connection the RPi is using.
This problem became really bothersome sometime between Christmas and New Year's Eve.