Well get ready for some more horror stories...
So, I got the monoprice cables, and the good news is that with those cables, the coupler solution seems to work. Haven't tested out anything in length (spent about 20 minutes doing VR stuff and regular play), but given drops would usually happen within minutes and I experienced none, I'm going to say that the certified cables definitely make this particular solution work.
Then comes the Sewell HDMI switcher. Up front, I'm going to say that I think I have to have a defective unit and have already contacted customer support to see if I could get a replacement. That said... here we go.
So I got four mono price cables. One going from the PS4 to the switch, one coming out of the switch and to the tv, then two going to/from the switch and processor box, back to the TV. Turn my PS4 on for what would be HDR mode. Nothing. Turn it off, hit the button on the switcher, and go to what would be my VR input on the TV, turn the PS4 back on, works. No fuzzies. Nothing. Figure I'll trun it off, try HDR mode again... again, nothing.
Try a different cable going from the switch out to the TV, put the cable that came with the Pro in, works. Try the Amazon basics cable, doesn't work. Put the pro cable connected to the ps4 and the switch in, then monoprice from the switch to the TV. Doesn't work. Return to the pro cable from the switch to tv, works for a bit. Reboot everything. Fucking doesn't work now. Also, the VR route doesn't work as well.
At this point, it has to be the switch right? I've tested literally everything else, and that's the only variable that I can't change.
Bottom line is... fuck Sony for this oversight. Playing Thumper for the first time with my Pro as well makes the oversight that much more stupid considering how good the higher res downsample looks in the VR compared to the base PS4. I really, really hope they make good on this and offer some mail in program or something. I'd be down with that.... but they won't.