One thing about the D&D and LS50W is that they digitize all analog inputs into PCM format. Your RME is virtually obsolete with those speakers. Vanatoo’s are similar in this respect as well. Since your main listening format is DSD, you may not like the conversion. I have some DSD files and I don’t like the way it sounds on the Vanatoo.
If you want powered speakers that are analog and do not convert DSD to PCM, I would look at something like the Hedd Type 05, Type 07, Type 20 or Type 30.
FWIW, I’ve listened to the Kii Three for an hour at someone’s house. I thought they were excellent speakers but my wife thought they were somewhat soulless. Have not heard the D&D’s but I expect that they are slightly better than the Kii’s In that regard.