For Lidarr I use Lidarr on Steroids (there is also Lidarr extended and a plug in script but I couldn’t get those going). Probably on me because I can’t get nginx going either.
I connected Deemix to it (you need a Deezer account) you can get MP3 for free, and with premium Deezer you can get lossless. All the music you want there.
There is also Soulseek for rare stuff but it’s manual and I cant find a way to connect it to Lidarr.