This was gonna be my next comment. If the screen doesn’t fix issue, might have to chalk it up to worn internals.
I’m in the same boat with my (ly6) 6.0, has low miles but a TON of idling hours. Oil pressure hovers around 10psi. Replaced all of the above, has to be worn internally. However, I’ve had it close to 4 years and put 40k miles on it with this oil pressure.
Interesting on the idle hours. But I guess a lot of idle wears engines, any engine.
My 4.3 Vortec in my 99 Silverado NBS slowly started to drop oil pressure. I think I noticed after I did the intake manifold, which was in the winter. By summer my check gauges were coming on. I drained the oil at some point and saw like a faint layer of glitter, so I knew it was on its last legs.
At the time I didn't have money because I was in the middle of a large home renovation project, so I just dumped 50 weight oil and kept on trucking. Oil pressure increased another 2-3 psi to about 8 psi. I ran it another 8-10 k miles. It still ran fine, no knocking.
After I retired the engine I tore it down and all bearings had severe wear: main, rods and cam. Clearances were 5-6 thousands compared to about 1.5-2.0 thousands specification. Probably could have overhauled it, but a junkyard 5.3 was much cheaper and a good upgrade from the V6.
Not saying that's your case (hopefully not), but may want to think about your options if it is.