Now I get it, you are using a U processor.
A few pages back a user got a similar issue on a U processor and we weren't able to solve it.
If I'm not mistaken those are low power CPUs from Intel, maybe it's related to that and they stripped out the GVT-g feature, that my only/best guess.
In the newly attached Diagnostics is nothing either...
But I think that U processors are not supported, you can only create a issue on Github, wait I saw now that you've created an issue about that...
I would rather stick to the guide from Arch, can you try to do it manually and see if it is working?