This seems to be the composer's website with an official way to stream the OST in recent years. I always felt that the music was a highlight of this show.

Some mirrors:

• Internet Archive: https://archive.org/details/dark-matter-ost
• Qobuz: https://www.qobuz.com/au-en/album/dark-matter-original-series-soundtrack-benjamin-pinkerton/ierbubbareott
• YouTube: https://www.youtube.com/playlist?list=OLAK5uy_nDwHfZ65GaKJi-IMQZG86_4xMAV_ZNX3Y
• Amazon: https://www.amazon.com/Matter-Original-Soundtrack-Benjamin-Pinkerton/dp/B0GXGTKY72
• Spotify: https://open.spotify.com/album/7GDndaykzwL3GGOEcFOh3P?si=Mv3stn7yQVCgWBjzO2kP8A
• Tidal: https://tidal.com/album/516593333