A warm DAC?

larseand OP
Prima Luna integrated

This "could" be your problem, HF transformer oscillation that rings like a bell. Starts at 10khz and shows in the square wave also. Especially with the Focals metal tweeters, it may excite them with hf sibilance etc..
https://www.stereophile.com/images/1214PLDPIfig01.jpg

See how the Focals are very high some 18ohms in impedance in the highs, this is where the Prima Luna also rings it ’s worse with high impedance.
You could "try" not too loud to load down the output of the Prima Luna just to see, with a 2ohm 10watt resistor this will then mimic the green trace which is flat.
https://www.stereophile.com/images/archivesart/707FOCFIG1.jpg

Cheers George

If he wants R2R instead of Delta Sigma then Holo Springs or Denefrips Ares are worth looking at.

+1 on that both very good sounding R2R.
PCM, Redbook, 16/44, 24/96, or DXD. is bit perfect when converted by R2R Multibit.
DS (Delta Sigma) can only give you a facsimile of it, and is also bit of a yawn to listen to. But can do DSD or SACD

Cheers George

To me the good R2R Multibit dacs usually have a bigger fuller sound with more weight behind them, I suppose you could call that warmer without being soft.

Cheer George