This is kind of a myth. Complex systems can have simple user interfaces.
Folks, the RME DAC is a complex machine and therefore its operation is complex too, that's unavoidable. Putting that amount of functionality in such a small screen is quite an achievement actually.
If users keep making the same errors it is because of the human machine interface, not because they are unable to understand it.
For instance, a confirmation window asking if you are sure about the loading/saving of an EQ profile would prevent many mistake, while keeping on with the poor user experience.
An overhaul of the interface paradigms may accomplish way more than that, of course, but as an interface designer I’m aware of the difference in the required effort between an UX redesign versus some inexpensive but effective tweak. Sometimes you have to choose the lesser inconvenience if you can’t fix it right.
In this specific case it may be better to have users complain about the number of passages to apply an EQ, rather than them complaining about losing half an hour of painful fiddling with the small knobs.