Hey CryoHeart,
don't feel alone and maybe resist to install Windows 10, because I have a similar problem with Helix Native on Cubse 9.0.40 and Windows 10.
After the installation and registering it, everything worked fine, but now, as soon as I click on the "edit" button in the Cubase mixer to open the Helix GUI, Cubase crashes. The GUI is not working at all and not reacting to any input. Still, the Audio engine keeps running.
I tried to reinstall it and it helped for exactly ONE time. The next day, I open the same project and as soon as I open the GUI of Helix, Cubase crashes again.
This happened to me with the VST3 and VST 2 version. Nothing helps but another reinstall.
Funny thing is though: as long as you don't try to upen the GUI, Helix works fine, meaning all the sound coming out is definetly what I configured before.
Have you got eny answer from the support?