HTX_Silverado

New to here and sorry to beat a dead horse but I have a question about oil viscosity/blend and how it relates to our oil pressure challenges. My 13' 5.3L with 125k miles experienced some oil pressure issues recently and I've been through the entire system and either replaced or inspected ALL the parts to ensure they are working properly. New oil pan gasket (had a small leak), oil pan pick-up tube, pick-up gasket, oil pressure switch, and yes even the screen. Local shop believes my bearing is going bad, however, there is no noise, no knock, no other symptoms at all that would indicate a failing bearing. My current oil pressure readings are directly correlated to the temperature of the engine. As I start the truck from cold, oil pressure is up near 35-40. As the truck begins to warm up and during normal operation, the oil pressure stays between 20-27. If I run the truck in tow/haul mode the oil pressure will tick up slightly with the increased rpm. To us it just seems that the truck is running slightly lower oil pressure. But that makes us a little nervous even if it does seem to be "normal" for these vehicles. With that being said, my dad and I have a theory that if we increase the viscosity of the engine oil to 10W-30 or move from a full synthetic to a synthetic blend, the oil pressure should tick slightly higher. I've also read plenty on the topic of running Dexos versus Non-Dexos oil (I've been running Penzoil Platinum full synthetic 5W-30) and it seems like there is some small room for flexibility with this. Does anyone have experience with alternative engine oil or can link another thread that covers that topic? OR is the consensus to just accept the lower oil pressure and live with it? Thanks for all the help J