Oh boy, I just had a classic #facepalm
I was looking into posting a video by embedding the direct link to the MP4 file, like so:
After embedding it, the post looked like this:
Trying to play it resulted in this:
So, I did a little research and came across ubuntu-restricted-extras. Tried to install it and realized it was already there. After some more frustrated searching I realized that maybe it would help if I unblocked the source website in umatrix...
I think in the future I should finish my coffee before I try to figure out computer shit.