SOLVED.
I downloaded the edited plugin from user ‘‘Elite’’ (on Discord support), (original plugin by user ''Mizzen"), and it worked for me. PID of my keyboard “0059”.
I’m posting the file in case it can help someone, until SignalRGB solves the problem.
Overwrite in the following path: %localappdata%\VortxEngine\app-2.2.28\Signal-x64\Plugins\Royal Kludge
(make a backup of the original file).
Good luck and regards!