Has firmwares, udev rules and drivers might be needed to get it to run on your distribution to get the wireless connection working.
As it outputs standard xinput we don't see any reason why this should not work with RetroDECK.
As none of the team owns a XAC we would love to hear from your experiences using it with RetroDECK. <br>
If there is something we in the team can help you with, maybe we can design a better general Steam Input profile for the XAC or any other feedback feel free to contact us on Discord.