Thanks for the support!
Engine was replaced with a factory new one and PPE LTHs, Z1 upper and lower intake plenums installed.
Honestly not sure what happened to the old engine at this point (I was not able to keep the old engine for diagnosis due to certain circumstances) but I am attempting to mitigate the possible causes that I have control over. Installed:
-Oil pan and pickup spacer (If/when I move to a race tire, I am considering an accusump)
-Bigger/brand new 34 row oil cooler (felt it too risky to try to clean out the old 25 anyway)
-Oil pressure gauge
-Using a thicker oil than the previous 5w30.
-Got a fairly conservative tune for better engine longevity hopefully.
-Planning on swapping in the Nissan Motorsports oil pump some time in the near future.
As a side note, aside from the obvious cage, seat/harness, also installed a differential cooler/pump, removed the AC and blower etc, Z1 clutch/flywheel (makes a huge difference on engine response). Car is 400-405HP (mid 340s whp) and 3185lbs with full tank of gas.
Phunks RRFP will be going in for next season and will cut a further 88.2LBS of moving/sloshing weight out of the car by running 14 gallons less fuel. Of course a pound or two will be added back by the pumping assembly.
A big thanks to Valkyrie Autosport for doing some fantastic work and getting me back on track!