Solving the CPU overhead won't increase performance by 20% just open it up for use with less powerful CPUs which of course would help a lot. That said, a 5700X3D would power this thing just fine and can be had for not much. Drivers need more work, your absolutely correct on this, with this in mind though, I personally didn't experience anything OS breaking while running the B580 and there is a fix/workaround for the horrible DX9 performance which is to use DXVK Vulkan wrapper. It's an old trick that has been around forever so it is surprising to me that Intel haven't baked it into their driver as a toggle for DX9 games.I don't expect it to be 7800XT standard but it's around 4060 performance. Worse, because of the CPU overhead/drivers/DX9
It's not good enough for the asking price. Sort the CPU overheard increase performance by ~20% and then I'll consider it.
However, when all is said and done, 3070/RX 6700 XT performance is not much when your trying to push above 1440p performance and/or maximum details in new titles. But for your casual 1080p and up to 1440p gamer its a valid option and its valid because of the similar options from Nvidia and AMD are priced so poorly or specced horribly or both.