So if I was thinking about safeguarding for the future, would I be better to change my mobo and cpu (i7 6800k @ 4.4) to maybe an i9 + mobo ( I can get an i7 clocked to 5.1 )or change my gpu and so I can achieve better fps in vr, or would I be better waiting.
For VR, your current CPU is still good. I upgraded from a 1080 to 1080 Ti over a year ago. And as Miguel has mentioned, the 2070 Super pretty much matches the 1080 Ti. It is a good boost to VR performance over the GTX 1080. It's still not perfect, it still requires balancing settings. Which you can see in my RR tuning guide. But you'll get a stable framerate and it will look pretty decent too.
For a balanced VR sim racing experience, anything around the performance of the 1080 Ti is very good.