;883589']Check this - https://rog.asus.com/forum/showthread.php?129310-ROG-Maximus-Z690-Extreme-onboard-LED-Stealth-Mode-i...
You can disable it only by Armoury Crate or bios settings. If You can't, then must be something wrong with your Motherboard. I would try to reflash bios if i was You.
I did reflash my BIOS from Version 3701 to 3701, but that didn't make any difference. I must clarify I have two systems running Armoury Crate. One on this R6E motherboard and one on a Maximus Z790 Hero. The Rampage 6 version is running correctly, it's the Hero system that is total crap. Considering the R6E has many more onboard LED's to detect and control, it's pretty amazing Armoury Crate works as well as it does on the R6E. Both systems have two LED strips connected to the MB connectors. The R6E system detects and controls both of them. The Hero system can't see anything--despite two uninstalls and reinstalls of Armoury Crate.
I did find a setting in the R6E version of Armoury Crate under the tab "Shutdown Effect" that worked to turn off the LED's on power off, so I'm happy with the R6E system. Both systems have Corsair LED fans and related Corsair controllers, so that complicates the environment for Armoury Crate. The R6E version seems to work and play with the iCUE program and I'm able to link Armoury Crate and iCUE in the Armoury Crate profile setup, but it's harder to do on the Hero system as it just sits there with the rolling balls trying to detect compatible hardware. After 20 minutes I have to close Armoury Crate because it's doing nothing. There are some hardware difference between the two systems--for example the R6E system is a complete dual loop custom water cooled hard tube setup, the Hero uses the Corsair H150i AIO CPU cooler with an air-cooled 4090. The R6E system has 7 Corsair LED fans, the Hero system has 13 Corsair LED fans, so the Hero system may be a bit more complicated to configure.
It does appear Armoury Crate settings were able to change the BIOS settings, but now that I've found the Shutdown Effect option the LED's turn off on power down.