I agree that the iFi PSU sweetens the sound, and have added an Uptone REGEN between the RPi and Explorer2:

Roon or Airplay over ethernet > RPi3 w/iPower > USB through REGEN > Explorer2

As a Mac user, I also like playing Audirvana Plus through this setup, but haven't been able to complete MQA unfolding in the DAC over Airplay. Anyone else able to accomplish this?

Server: Audiolinux Roon NUC w/HAF room correction and crosstalk cancellation
Theater: 218, Allo Signature, miniDSP, HD621, C61R, DSP5200SEu, 420, 33, NHT subs
EtherREGEN w/Finisar fiber, Shunyata Denali
Living Room: RPi4 Diretta Host & Target, Ghent USB > Singxer SU-6 > AES NA M-Links > DSP9
Shunyata TritonV3, LHY lps, Farad Super3, Stack AUVA feet