Hi,
Same problem here.
I have an Asus Strix-E X570 and a Level 20 MT aRGB. The Asus cable came with the case is plugged in the adressable 5V 3 pins RGB connector of the motherboard, and it goes to the fan controller card of the level 20MT.
The three fans works perfectly without the motherboard. When I press on RGB button for 3 seconds on the level 20, all fans blink 2 times and only the top fan is partially and poor illuminated (think one led is illuminated). Asus Aura change the color of the fan led in coherence with other stuffs in the rig, the synchronisation is good. Sometimes I get it work when I unplug the SATA alim, and change the RGB mobo header when system is ON. But when I reboot, during the post the issue is caming again. I don't think it came from a poor connection, I tested with an Y adaptor with better connection between mobo and the asus cable of the level 20, with no success. And two times I get it work, the issue came back when i changed profiles on Aura or I reboot the PC, let me thinking this is a compatibility/software problem between Aura, the mobo and the controller.
See you,
Julien from France