Thank you to Dave Stevens for the Most Compleat Reply Award.

1) I changed the oil filter, found no sign of a bad gasket.
2) I removed and inspected the oil pressure switch. No visible failure.
3) Oil is coming from numerous places, on closer observation on the lift.
4) I replaced the valve cover gasket. It was brittle.
5) The rear cam plug showed no signs of failing.
6) I installed IPD's rear cam plug cover.
7) I installed a new Mann filter and 5w-30 synthetic oil.
8) Installed a new oil cap gasket, it was brittle.
9) I cleaned under the front of the motor and test drove. Still some fresh oil leaking but now towards the rear.
10) Inspected flame trap, found it plugged 95%.
11) New flame trap installed, a new S hose to it also, which was perished.
12) All related hoses checked out clear. I did not disturb the breather box.
13) Capped off two evap emissions schme at the throttle body. Hoses are perished below anyway, and I hate evaporative emissions systems with a rancor not seen since Stalin enslaved eastern Europe.

Now the rubber glove on oil filler test shows marked improvement, but still some pressure. Tomorrow daughter drives it to work then I'll lift it again Saturday and see if leaks have abated. My hunch is I'll also have to clean the breather box and replace the O ring at its base. Icky poo dirty hands, lots of fresh clean oil showing there before flame trap renewed.

Helpful post from those mad lads at turbobricks:

https://turbobricks.com/index.php?threads/guide-to-the-volvo-pcv-system-with-video.158981/