Hey!
I've got the same problem;
So I'll guess I'll try a workaround.
I'm going to try to install the windows 11 installer on a USB-stick and install it on a new drive I'm putting into the system, to check if I get any error messages or what really happens when you try to install Win11 on the i7 6700k. I'll update with my findings.
Edit: Seemed to install on my 2nd PC with no problem via a USB-stick. Guess it works.