Sorry, but I do not fully understand your point.
Even though I use OKTO DAC8PRO, I always keep the individual channel volume (and the total volume) in DAC8PRO at -4 dB for many reasons including safety concerns. If you use independent system-wide DSP (XO/EQ) software like EKIO receiving all the audio signals from Roon, JRiver, browsers, Adobe Audition, AudaCity,
etc., you can use that system-wide DSP (XO/EQ) software center's individual channel volume (gain) even on-the-fly and you can save/reload your settings.
Furthermore, if you would use preamplifiers or integrated amplifiers receiving DAC-ed analog signals, you may use such individual amplifier's volume controller for flexible relative volume/gain control in your active multichannel system, I believe.
I use HiFi "integrated amplifiers" and active L&R sub-woofers each of them has IR remote controller for safe and flexible on-the-fly gain (volume) controller, and also it allows safe flexible on-the-fly relative gain controls depending on the "hearing tastes" and/or "hearing abilities (especially in high Fq)" of the listeners/audiences, as I shared
here in my project thread and
here on the remote thread.
( I always have protective capacitors in the SP high level signals going into my treasure Be-SQ, Be-TW and metal-horn-ST.)
Just for your reference, the following posts on my project thread would be of your interest.
- Where to control master volume and relative gains? #058,
#060,
#062,
#191-
#221
- A serious jazz fanatic friend came to my home for audio sessions using my multichannel multi-driver multi-way multi-amplifier stereo system: #438