You can use Audacity to record from the Speaker output internally. Just make sure there isn't anything else running that could interfere or make noise (anything connected to push notifications), and you should definitely make sure volume isn't too high else it'll peak and distort.
Avoid Spotify Downloaders, they are a Scam that often just searches for the music on YouTube. For true Spotify exclusives (or ones that just aren't on YouTube) the songs from those will be wrong, or if they're a downloader that is better at matching the songs, will just error because it couldn't find it.