The server you’re using is less likely to support Rock and may not support USB.
Rock in my use limited DSD to 256 when connected to a DAC that could support DSD512 via USB.
I use DietPi and when using Roon Sever it gave me full DSD512 support.
As @DrTone mentions, Rock is the limitation here and more so with an unsupported device.
Windows 11 Pro, would work if you have the driver available for your DAC.