Usenet. Plenty of music in lossless (FLAC) format. Use NZBGeek and DrunkenSlug as indexers. Sabnzbd to download. Lidarr and Prowlarr to automate everything. Add an artist, click to download an album, and it'll search for the album, download the NZB file, send it to Sabnzbd to download, then tag and organize the files once it's done downloading.

For music I'd just get a block account: https://www.reddit.com/.... Essentially, you pay for some amount of data (can usually get 1TB for US$5-15), and they usually don't have an expiry date, so it could last you for years. Some providers have monthly plans with unlimited data, but a block account will end up way cheaper if you just want music.

For rarer music, Soulseek is very good. It's a peer-to-peer service from the KaZaA and Napster era, but somehow it's survived until now. Since it's peer to peer, downloads are quite a bit slower (you're relying on the upload speed of individual users - each download comes from only one user) but it's a great community.