DonnyUv2
Right. Generally streaming hi res you need a good quality hifi setup and a good Internet connect like home internet, not a phone network.
Most modern receivers support hi res streaming, but certainly not phones. You can also get a standalone streamer that will plug into standard analog inputs.
A DAC is a standard part of any digital audio device. Your phone, tv, CD players, etc all have one. The one in your phone is just not equipped for hi res. You can buy external DACs that will work.
So minimum to get hi res Apple Music into your particular setup would probably be iPhone or iPad (running on home wifi) > external DAC > analog input of amplifier.
Hi res uses about the same amount of data as 1080p video.