You need to select the Hifiberry DAC option and from adp shell install the IQ DAC.
There's a line under 'Audio DAC' section in /boot/config.txt that you need to modify to load the driver for your audio DAC if you're using something other than Hifiberry DAC+.
There's a script you need to run to change the audio device and enable the driver for DAC.
Code:
su
rpi4-audio-dac.sh
Then you still need to manually edit the line in /boot/config.txt to change hifiberry-dacplus -> allo-boss-dac-pcm512x-audio or IQ audio dac which is supported on kernal.
If you have trouble after this check 'dmesg' output that the driver for DAC is loaded you can see it listed as ALSA device.