Are you using a Windows N or KN edition of Windows? https://www.howtogeek.com/322112/what-is-an-n-or-kn-edition-of-windows/ which is possible if you are not located in say USA or Canada. If so then you may not have the Media Feature Pack for your Windows version installed which provides the codecs needed in order to fully support the HTML5 players used by sites all around including Youtube. Without the codecs you may still be able to view older Youtube videos but not recently uploaded or live stream ones for example.

https://support.mozilla.org/en-US/kb/fix-video-audio-problems-firefox-windows

I am using Windows 10 Home 22H2, and with how I have things such as Windows Media Player & am in the US, I'd imagine i have the proper media tools already installed. I'll try updating my PC tonight to see if that fixes anything, but I'd imagine that there wouldn't be much change.

Provide more detail about your computer. Desktop, DIY, or Laptop? Are you WiFi or plugged in? What is your network connection speed? Post a screenshot of the performance tab in task manager so we can see the specs. Provide a link to an example video.

The Cable Guy only show up to 480 on my mac via wifi, but I'll see what I get on my other laptop that's plugged in.

Does it still happen in Troubleshoot Mode?

I get the same 480 on a laptop plugged in. see screenshot

I think most of these free with ads movies on that channel are hidden for me due to location.

I do find the Buy or rent version where the one minute preview goes up to 1080p. Perhaps that is why the so called free with ads version of The Cable Guy if available is only up to 480p.

I found out what was wrong; i had media.mediasource.enabled in about:config marked as false when i was fiddling with something a while ago.