Hi. I am using Rpi4 + Volumio > USB Locus Nucleus cable > Waveleght Proton USB DAC > Hegel H200 > Phonar Credo 100 floorstaders. Very happy with the result. You can use HAT DAC (like HifiBerry, JustBoom, Allo Boss etc.) HAT is basically module you plug in and then enclose in 1 box, with Rpi4. HAT is least expensive version, but separate DAC is better. Check this, John is quite good in explaining things: https://darko.audio/2020/01/raspberry-pi-audio-streaming-101/