Just curious if the EQ changed any of this for you. I had the RME and I heard EXACTLY what you are describing and I sold it. I never did tinker with the EQ all that much, I didn't think it would make that much of a difference.
First I must say that I had a grace design that not really worked with usb and I don't have a computer in my room.
Now when I bought the RME I was also considering the Oktoresearch dac and the Matrix dac.
The one thing that helped me make the decision is the reputation of the company and the product and the praise here and the features. I also bought the Microphone from Minidsp which I could now use with my laptop by usb and the usb input of the RME.
I then starting measuring. And it was clear that something was not right. And by the help from the RME forum. I found out quickly that the phase wasn't set right on my subwoofer. He also chose to set the speakers a little different as well as the subwoofer. He also said to match the main speakers to the subwoofer. This already made a huge huge difference.
Now I posted the curve again. But I tried the EQ myself also to get rid of some anomalies in the curve that were less now. And this made a difference in the sound. Much more than I thought possible. The level of playing of my system has gone up much greater than a slightly better spec would do. There is nothing wrong with the RME. And yes others will give you the same performance. But not the same features. My system is sounding better than ever.
The biggest difference is measuring with a microphone, someone who can help you figure out what is happening with the curves and room. I hope I helped you. And otherwise, just ask.