I had a damaged LED Cinema Display 24". Replacing the PSU card allow me to repair it but it is working at full brightness. Thanks to this work of Mac84,
https://www.youtube.com/live/JNqIYdVm6YI?si=3lPWSeJnxW8pLNvg
I understood better the possible issues and some repair options (LED strip, bypass backlight regulation, etc)
Just annoying is the full brightness that you cannot adjust.
Well, I finally found this today, and it is gorgeous!
https://github.com/MonitorControl
It allows you to control independently brightness of each monitor that is connected to your computer.
Mac84, not sure if your wife is still using that LED 24"Cinema Display, but this might interest you.