I can’t name a combined DAC/amp has a perfect balance between the capability of the DAC vs. the amp sections. One aspect is almost always somewhat better than the other.
With the RME ADI-2 DAC it’s the DAC that’s the better of the two pieces. With something like the SPL Phonitor x then it’s the amp that is the better element. Maybe the closest balance is between the DAC/amp sections of the Holo Audio CYAN (PCM version).
The amp-stage on the RME unit isn’t bad … it’s just not quite as good as it needs to be to get the absolute best out of the DAC section. Mostly it’s about raw resolution, micro-dynamicis and slam. And given how good the DAC section is, and how good the overall unit manages to sound, it’s not a big deal at all … as long as your headphones don’t demand so much power that other aspects of the amps performance start to become an issue as well.
It’ll drive all of your listed headphone just fine in terms of raw power. The Andromeda, HD6XX and maybe the HD58X are capable of more resolution and micro-dynamic subtelty than the RME ADI-2 DAC’s amp stage will deliver. But then the Andromeda and HD6XX will continue scaling beyond the capabilities of many much more expensive dedicated amplifiers anyway.
Now, with the Andromeda I find they’re too bass-heavy and a bit tonally off when driven straight out of the IEM output on that unit (and, in fact, any unit with such a low output impedance … the Andromeda really sound best with about 2 ohms of OI). Using an iEMatch inline with them will largely take care of that. Because this change in tone/balance at low OI is down to the varying impedance curve of the IEMs themselves, you can’t EQ it out perfectly … hence the recommendation for the iEMatch.
This is a long winded way of saying that overall, you’ll have to spend quite a bit more than the asking price of the RME unit if you want a DAC that’s as good AND then an amp that can do the DAC (and the headphones) justice.