I think it pairs fine…RME is pretty neutral sounding so it just kind of gets out of the way but if I had to describe it, the RME is a bit sharp and flat sounding but still engaging. It’s probably not the best DAC to pair with the Aeolus synergistically but it’s not bad by any stretch. Looking at the analyzer while listening to music makes me forget all about it tho!
As for the Bifrost, I’ve never owned one but there are many people here that use it…you can probably find some impressions on the Bifrost thread…