Burning oil

Not sure why you have ruled out valve stem seals....??? The fact that the oiling increases with the PCV blocked could well indicate it is in the seals/ guides.

I'd pull the intake or work the borescope down the intake runners and inspect the tops of the intake valves. If they are reasonably clean, then it is from the cylinders/rings.

So just a hone job on the cylinders? Did you measure the cylinders for taper and out-of-roundness? Your 2nd compression ring does more for oil control than it does to seal compression. So the rings may not be sealing as well as you think due to the cylinders not be straight and true.

Any chance that the 2nd rings got installed upside down? Many/most of them have a specific 'twist' designed into them that makes them more effectively scrape oil downward off the cylinder walls. If they are upside down, the 2nd rings' oil scraping ability is lost.