Monitorian (Windows monitor control app)

Not aware of a similarly polished GUI tool on linux, but I use this: https://github.com/rockowitz/ddcutil

It's been super convenient having found all these tools (I use all 3!) for software control of monitors recently.

And as usual, Nirsoft have a tool: https://www.nirsoft.net/utils/control_my_monitor.html

On my monitor I can even adjust the dark boost settings too (0xEF on the VG279QM)

An alternative for us preferring CLI tools, is the nir-set of tools. Put nircmd (https://www.nirsoft.net/utils/nircmd.html) somewhere in path and add an alias to it. Something like this,

    alias bri='nircmd setbrightness'

When I had an external monitor plugged in, I used monitoran.

So Mosaic works with certain nVidia graphics cards to make monitors appear differently to the operating system like Windows, ie you could have 2 or more monitors but windows will see only 1 ultra wide monitor.

Every night I set brightness of both monitors to 15, and every morning I raise it back to 30.

I've been hoping for a tool like this for years.