Sorry for the bump but I cannot seem to be able to edit my previous post anymore.
It turns out the Steam integration plugin I had was still causing some errors despite it being disabled so I went ahead and deleted both disabled plugins I had, no luck.
I tried creating a new theme in case the default one was broken. I could not get past the "save" button. When I went back, there were many new themes with a generic name. I tried deleting all of them, including the default theme. I am now getting an error due to no themes existing at all. I don't know why or how I was able to do that.
Enabling dev mode seems to work and I was able to create a new theme with it enabled. While it's enabled, I also don't see any of the `ips is not defined` / `jQuery is not defined` JavaScript errors. They come back as soon as I disable dev mode.