I have a very similar problem to “How to get coolbits working with 20.2.1” (which is also on the Manjaro forum, but I can’t include a link to it). Unfortunately, just using
optimus-manager isn’t a solution for me, because I have and AMD iGPU which is why I (have to?) resort to
video-hybrid-amd-nvidia-prime. My dGPU is a Nvidia RTX 3070 mobile and I use Manjaro KDE. Is there any way for me to set coolbits without causing a blackscreen at startup?