There is https://www.ddcutil.com/ It has a command line utility and a qt GUI. Unfortunately the GUI is a bit convoluted, because it exposes every option that you can change on the monitor. I once almost bricked my LG monitor, because I accidentally locked the hardware buttons on my monitor, via an undocumented manufacturer specific option.
> Unfortunately the GUI is a bit convoluted, because it exposes every option that you can change
Wow, color me surprised. That doesn't sound like a desktop Linux app at all :)
>I once almost bricked my LG monitor, because I accidentally locked the hardware buttons on my monitor, via an undocumented manufacturer specific option.
Reminds of the good old days of late 90s / early 2000s desktop Linux, when the wrong video timing settings in your XFree86 config could make your CRT monitor (almost literally) explode.
But I'm sure 2022 will be "the year of Linux on the desktop", finally :)
The same author also made some kind of UI for it but I haven't used it so I don't know how it looks or performs: https://github.com/rockowitz/ddcui