Like sound, there are multiple things that affect the overall display settings on a monitor.

There are settings you can change on your monitor, your desktop, and frequently the application you are using and they all impact each other.

If everything else is dim, but not too dark, bring up the show and something else you think looks fine on the screen at the same time to compare how they look when you change settings.

Check to see what mode your monitor is set for if it has them. Movie will frequently be darker than sports or gaming and these presets can affect some media very differently compared to each other. For me, bright games look basically the same but others go from darkest night in movie to hey cool there are things in the shadows in gaming mode.

You can also increase your monitor’s brightness and gamma a bit and see how much it helps without making other things look weird. I would mess with this after playing with the monitor’s modes.

You should be able to notice some difference playing with those settings, but if they are not enough or don’t seem to have a lot of effect check your system settings and your video card/onboard video settings. Those can be multipliers for the monitor settings so you might have to dial some things back if you find one setting here that makes a huge change.

Eventually you might need to make adjustments in a few places so things that looked good already still look good while the stuff that is too dark is easier to see. For me switching from Movie to Standard in the monitor’s View Modes had the biggest impact of any setting at addressing the media that was far too dark. Cranking up the brightness and gamma wasn’t enough on their own and they just made the bright stuff washed out.