Recording Computer Audio Comes Out Sounding Tinny

I’m prepping for my first LP and I have an issue with recording not my own audio, but the game audio. It’s not outright hideous, but the audio quality is rather poor. It sounds hollow and tinny, like I’m holding a microphone up to my speakers, even though I’m recording off Stereo Mix. This isn’t a software issue, as both OBS Studio and Audacity produce the same result. Here’s a demonstration, using as a sample the classic musical number “All Hail Shadow”…

First is the original file in crystal-clear YouTube quality. After that are two recordings of it, both done in Audacity. The first is “Stereo Mix”, the second is “Speakers (Conexant SmartAudio HD)” which I assume represents the state of the audio right before it’s played. Neither are very good, with SmartAudio being slightly worse, as based on the waveform it ludicrously overemphasizes the treble.

I don’t know much about audio and can’t think of any reason why this would possibly be happening, and any help would be appreciated.