hihi, my initial proposal to Michael here is all software only. please click on „image“ in link above…Meanwhile I do it by using Pis instead of the Mac running NAA with blackhole 
By using Shairport-Sync or Airport Express Gen 1 I am running ALAC 44.1/16. So Airplay 1 upsamples everything to ALAC, e.g. Spotify, MP3 128 from Web, …. HQPlayer does the rest…Sounds nice and is super comfortable imo. No wires, cables, etc at iDevice. All your iDevices can stream to the Airplay endpoint. Just a click. Did not dig further into it, but Shairport-Sync allows Output to Jack too. I have it running on Ubuntu Server too next to HQP. So there should be a way to „pipe“ to HQP from Shaiport-Sync imo. Do not know so far, how HQP NAA can handle Jack. There is Airplay 2 option for Shaiport-Sync too, if you like to run Shairport-Sync this way. You can use SoX, exchange the ALAC decoder, integrate REW,…So, all possible…But super most important by using Airplay 1 with Shairport-Sync you avoid on the input side the compression to aac instead of ALAC. Did write at the linked thread a bit more about my experiments with that. Meahnwhile - to be flexible e.g. for a CD Player via TOS - I am using a PI 3 running RopieeXL with a Hifiberry Hat for digital input (Digi+ or so). Running NAA on that PI too. So, that PI solution is a bit similiar to @dabassgoesboomboom way here for Michael. But I am fixed in samplerate. There is a Hifiberry Hat switching samplerate but I did not get that running… https://www.hifiberry.com/docs/hardware/comparison-of-hifiberry-cards-for-audio-recording/ This is the „fun chain“. For serious listening using Roon to HQP to Pi NAA…+++ So, you catch the idea, I guess. Sure you are capable to run with that setups lossless, bitperfect too in some constellations. E.g. running Qobuz or running output from CD…But keep in mind this way so far no automatic samplerate switching please.
( in regard to Spotify, RopieeeXL has Libresport as well. You prob. know. RopieeeXL is super in parallel to Sonore Sonicorbiter/microRendu )
++Edit, puh 9 edits for this post. But I believe it is now more understandable…However for software only pls. click on „image“ in link above and modify according to your preferences.