I'm not sure if it will bootup with a default desktop as I do mine a little differently. It might bootup with an old style text based menu system that you navigate with the arrow keys. The Pi needs to be connected to a network as any additional software will need to be installed over the network via the DietPi menus.
What software do you plan to install on DietPi? The DietPi menu system has a HUGE list of optional software you can tag for installation. My Raspberry Pi's are pretty simple as the only audio related software I install is Roon Bridge. I might also have ALSA installed with the Linux audio subsystem so it can communicate with the USB DAC.
