Video players (multiple sites) randomly darkening and tinting grey?

Hi, For a few days while I've been watching content on YouTube and several other streaming platforms, I have noticed that my screen will randomly go completely dark, then slowly fade brightness back up. While it is fading back in, there is an intense grey tint over the whole screen that takes longer to fade away than it takes for the brightness to return to (relatively) normal. This seems to only be happening when I am in full screen, and I truly have no idea what setting or issue could be causing it. At first I thought it was part of a video I was watching, but now that it has happened across quite a few videos and several different streaming platforms, I figure it must be something to do with the browser itself. Sometimes when it goes dark, the screen stays practically black for several seconds before beginning to fade the brightness up, sometimes it is less than one second that it's dark before going grey and fading back up. Interacting with some buttons seems to make it go back to normal, although when I click on settings on a video for example, when I click off of it/close settings, the screen goes back to however grey it was when I opened settings. Sound continues normally the whole time, and the only thing that seems to prevent it from happening is not using full screen, which I don't want to have to resort to, but it has become rather annoying and confusing. Any help is appreciated!