Update:
I realised that the issue was extending to other VR games so my approach to this changed.
After extensive testing, BIOS firmware installs and uninstalls, with most of my focus on the mobo, I hit a hard wall.
Yesterday though I had a new thought, and started investigating the Reverb G2 and its possible issues. I'll link the forum (Elite Dangerous) that helped me find a solution.
In summary, for anyone running a HP Reverb G2 with a B550 or Z570 mobo, the VR headset and the mobo do not speak with each other properly (some claim the HMD is too hungry for what the AMD board can supply - power wise - from the rear USB ports). It seems to be more of a HP problem than an AMD issue. There are two work arounds though:
1- Plug the VR USB to a front USB A or C connector (dedicated mobo USB ports that are wired to the front of your case) **this worked for me**
2- Buy a PCIe USB 3.0 card and plug the VR in it.
I was just about to give up and return my mobo and cpu to the local seller and then I found this option
Links are not allowed in this forum, happy to send anyone experiencing this problem to the right path if interested, but this post pretty much covers the main point.
Cheers.