Gary gave great advice about using a better sound source for MIDI. What you have now sounds like toy sounds compared to what you could get for a reasonable investment, such as Coyote Forte (not Wavetable).

I would like to return to your original post. Yes, there are better ways to connect your laptop to your PA than the laptop's headphone jack. The ones I know connect via USB to the laptop and give either 1/4" or RCA output jacks. Now, the audio PLAYBACK quality of most modern laptops is pretty good with the built-in sound card (recording is an entirely different story); nevertheless, I will do whatever it takes to avoid using those 1/8" headphone mini jack connections in a live setting. The jacks go bad quickly and they easily produce noise. Just touch one when it's connected to a PA and you'll get a loud annoying cracking noise. You don't want to do that to your audience.

As far as playing back RealTracks, this is audio so as I mentioned, the laptop does a pretty good job with that as long as you keep the gain up.

BIAB 2025 Win Audiophile. Software: Studio One 7 Pro, Swam horns, Acoustica-7, Notion 6, Song Master Pro, Win 11 Home. Hardware: Intel i9, 32 Gb; Presonus 192 & Faderport 8, Royer 121, Slate VSX, Adam Sub8 & Neumann 120 monitors.