No background noise on TCL 55Q550G

I have been having an issue for the last two weeks with my TCL 55Q550G. I just got back from a long vacation, and had left the tv unplugged for about a month. Now I am experiencing an issue I haven’t had before, where there is no background noise/music during movies and tv shows. It is particularly pronounced in this scene from KOTFM, where there should be background music the whole time. You can hear it spike just briefly a few times while Leo talks. I am not sure what could be causing this. I’ve searched all over the internet and it seems like maybe the issue could be that it is trying to use surround sound despite not being hooked up to a surround sound system (I just want to use the built in speakers). I am not sure what settings I would need to change to fix that, though.

I have experienced this issue on both the Max and YouTube apps on the tv. The video on this post is of YouTube running off my laptop plugged in via HDMI, and this issue is still happening.

I have tried: Factory reset Reset as “Basic TV” instead of Smart/Google TV.

This is driving me crazy. Any ideas?