No volume control when playing native DSD files

My system is comprised of an RME ADI-2 DAC, Hegel H20 power amp and Spendor D7 speakers. I am presently playing my CD library from a USB drive attached to my laptop and streaming Qobuz from the same laptop.
The problem is that, if I want to play DSD files in native format, I would not have any volume control. DoP would work, but DoP is not DSD native. I listened to some DSD albums in native format on another system and DSD sounds better than my PCM files from CD or Qobuz, as well as better than DSD over PCM conversion made by my DAC.
The question is: Do I really need an analog preamplifier in order to play DSD files in native format, or is there a workaround this whole issue?
Your help in this matter would be highly appreciated.

Your DAC can’t do volume control with DSD. Check manual page 16 paragraph 8.8 “DSP Limitations”

DoP is native DSD, this is a big misconception. If that restores volume functionality, switch back to DoP. There is no conversion or alteration of the DSD information when using DoP.

Hopefully to add some additional detail on this topic… There actually is a conversion process when going between DSD and DoP (DSD over PCM), although the recovered DSD should be identical to the original. To create DoP the original DSD bitstream is encoded in PCM frames which have a flag that designates them as DoP. When the DAC receives the PCM frames it identifies them as DoP and then unpacks the data back into the original DSD data. Some listeners claim to hear a difference between DoP playback compared to the unconverted original DSD, and if there is a difference it may be due to the additional processing required to convert DoP back to DSD and any noise that the processing may add to the analog output signal.