I'd highly recommend just going with local flac files. You're going to get far more quality, reliability and value for money by just using local files. Music streaming is extremely unreliable, expensive, and an album can disappear overnight and there's nothing you can do about it. With local files you can have what you want, no one else can take it away and you don't need an internet connection just to listen to music
Back in the days, I ripped my CD to flac about 3000. between 5 and $15 per CD... let's call it 15,000 in CD,
Spotify Premium is about $14 per month...
The sound quality is IME as good as CD...
They have a library no single human this side of the billionaires (and even then...) can fathom, let alone acquire.
The UI is good.
Spotify-connect is the best in the industry
Their recommendations are decent.
Spotify and its UI, can work with your current library ...
And if you are in the IOS ecosystem, there is Apple Music and Apple Classical... Lot of lossless files, lot of Spatial Audio...Immense Library
IDK the exact price but standalone it would be about the same as Spotify.
Streaming is the new reality, one can choose to continue to but their own files or CDs... Streaming offers much more music, convenience and similar to equal sound quality all that for around $20/month. The price of buying one (1) CD per month ... years ago...
Peace.