Here are some descriptions of what others have been up to with their Dx0Q.
In June 2022 I heard from Krzysztof.
Thanks to the mini PCIe connector it is possible to turn this thin client into pfSense/OPNsense firewall. All that needs to be done is to work out how to fit the additional RJ45 port. There is a convenient point by the DVI connector. Having cut out a suitable hole for the port I then cut down the bracket carrying the port and used a couple of rivets to hold it in place. See the photos.The CPU supports AES-NI instructions and scores rather well in Passmark, sporting 1400+, which is enough to run 1 Gigabit WAN connection with vendor's re(4) drivers.
An internal view showing the completed modification.