The worst ever suggestion and unfortunately the most upvoted. Do not ever download music from youtube, free-mp3-download was a front-end for deezer with flacs and 320 kbps mp3 and music on youtube is only about 160 kbps, that's kinda okay for streaming but absolutely ridiculous if you want to download and keep it.
I download it from youtube because that's where I found it, and I'm not entirely sure what's easier than just copying/pasting the link of the page I'm already on. I'm very confident other methods have better quality, but easier is a big statement.
It was possible to download lossless FLAC files (they got them straight from Deezer) though, so higher quality than anything downloaded from Youtube etc.
YouTube is absolutely unacceptable quality. The difference is clearly audible even on $5 earbuds. I feel sorry for your ears if you don't hear the difference, but the vast majority of those who care enough to download music will be able to tell the difference.
I personally pay for Deezer HiFi and save the FLACs locally. Friends mostly do the same with Tidal, but both work well for this purpose.
If you want to find FLACs without paying for a service you can check out rutracker. It has torrents for discographies from a lot of famous artists. Alternatively, you could find a stolen account for one of the previously mentioned services, but that goes too far for my morals because you're hurting a normal person with a hacked account.
Despite all the naysayers in the comments, this is the correct answer. No ad-riddled websites, no weird guis. just "yt-dlp < url of whatever you want to rip >" in bash.
Lots of people responding to this need to acquaint themselves with the raw power of yt-dlp. It isn't just for YouTube. You can rip Deezer and other streaming audio services. You can rip pretty much any video site. It even takes RSS and M3U8 links and will rip live streams.
Well I've found you can avoid the extra sounds as long as its available on YouTube music specifically, as that is a music specific platform but you have to only select from the songs section and not the Videos section. You get less selections than you would've before but not really since those extra ones weren't even songs, but rather music videos.
Also Lyric videos basically never have any sounds in them.
(Doesn't address the quality issues since many YouTube videos are limited in audio quality, I've found downloaders that can do it but it's hit or miss).