I think the big thing both Roon and Audirvana achieve sub-optimally is just overall application performance and user experience. They do have a ton of features which help in managing massive audio libraries, far better than Spotify or Tidal alone. But, Roon legitimately feels like a browser app they threw in an iframe and nativefied. Audirvana is better IMO, but isn't as good as Roon at auto-discovering album artwork and metadata-ifying the connections between your local songs for hyperlinking and discovery.
The critical thing that I love about that methodology of music playback is the "synthesis" they both do of Tidal and your local music. There is a ton of music out there that's inaccessible on (all!) streaming services, and every audiophile I know eventually starts amassing a collection of lossless files from Bandcamp/etc. Neither a streaming service nor your local library alone is ever the "complete" view into all the music you want to enjoy; you need both, synthesized into one integrated view. Google Play Music used to be a decent solution to this, not the greatest quality but it solved this problem well, but then Google nerfed it into the ground.
There's still a lot of work to be done in this domain. To be honest, my go-to for local music playback is the same app I've been using for a decade after the fall of Winamp; Foobar (Windows). Its simple, ridiculously performant, infinitely customizable, and works great.
I have a Focal Clear, Schiit Lyr 3, Schiit Bifrost 2 and I can not tell the difference between Tidal and Apple Music. There are tests online which people regularly post on Head-Fi and Reddit which also shows that almost all people can't distinguish lossless from high quality lossy encodes.
> or rip CDs yourself. This will give you the best quality
No it won't.
As Apple describes in their guide for Apple Music they have, "dynamic range that’s superior to red book CD audio" because they transcode from the high-bit masters.
I'm sorely tempted to build my own library/playlist management front-end on top of Spotify's API. They're the only streaming service I've found with an official streaming/remote control API, and with upcoming lossless support (albeit only CD-quality), their library with a tailor-made UI seems like the best trade-off I'm going to get in a music service.
None of this is an issue if you rip your own CDs or buy lossless from reputable sources in my experience. Spotify you're at the mercy of whatever crap Spotify has been given.
I find it's only good at playing random songs on giant playlists, or playing the radio. Managing a library of albums is a huge pain and I still don't understand how it's supposed to work.
Then there is the problem of questionable digital masters. There's 0 transparency into the mastering process and what Spotify uses. As you've observed, some things just sound really awful on Spotify.
If you really want the best, I suggest Roon + Tidal subscription for playback. Then use Qobuz/Bandcamp/etc. to purchase lossless FLACs to import into Roon, or rip CDs yourself. This will give you the best quality, and you can be certain the source quality is good. You can use Tidal lossless for streaming things you don't buy (but the selection is much more limited). The Roon UX is way, way better than Spotify for managing a large collection of albums.