Physical buttons have all but disappeared from everyday devices. You will find very few phones have anything more than a power button, volume buttons, and perhaps three other buttons for navigation but that’s about it. Devices like the Chromecast have no physical buttons whatsoever. It might be good for aesthetics but sometimes a physical button is better than soft ones. That said, physical buttons can break and often there is no substitute for their function. If you need to adjust monitor brightness but the buttons on your monitor are broken, you can make use of third-party apps, or you can try using the Windows 10 default brightness switches.
Windows 10 Brightness Controls
If you have a laptop, this is a no brainer. The Function keys also control brightness, volume, and the WiFi switch. You can use them to adjust monitor brightness.
If you have an external monitor, or you have a desktop system, the function keys may or may not be able to adjust the brightness. Your monitor should have dedicated buttons for it but if they’re broken or damaged you can adjust brightness from the power plan.
In File Explorer, enter the following in the location bar.
Control Panel\Hardware and Sound\Power Options
At the bottom of the Control Panel window that opens, you will see a brightness slider. Use it to adjust monitor brightness.
Assuming the above built-in tools for adjusting monitor brightness have failed you, you still need to manage the brightness with broken (or absent) physical buttons. Download a free app called Dimmer. Dimmer can manage only brightness, and not contrast. It adds a sort of screen on top of your display to adjust the brightness. It isn’t changing the brightness of your monitor like the physical keys on it would.
Use the slider to adjust monitor brightness. Move it left to increase brightness, and move it right to decrease brightness. Dimmer works only with external monitors.
If you have more than one monitor, or you also have a need to adjust brightness for an internal display i.e., your laptop’s screen, use an app called Pangolin Screen Brightness.
Pangolin Screen Brightness has support for multiple monitors. It doesn’t give you a free range slider like Dimmer does but you can use it to control the brightness of multiple monitors, and apply a color filter if needed. Like Dimmer, this app also applies a filter to dim the screen. If you exit the app, the screen will return to its previous brightness level. This app cannot change the contrast level of your screen.
If you have distorted colors, or hue and saturation problems on your screen, consider refreshing the color profile for your monitor.