Yup. That’s your issue. Disney+ outputting Dolby 5.1 and your speakers are stereo.
Well it's still their fault for not making sure their audio works on a normal, non-surround setup
Also worth noting that we switched the audio track to Spanish and you can hear it just fine.
That's not what the link says. In fact it is specifically saying it should be working in stereo but tdolby surround has missing channels.
This shouldn't be an issue anybody has. We've had Dolby surround sound for over 40 years now, and everything was fine until recently. We had quadrophonic sound years before that.