2018 Ram 2500 6.4L: P0300, P0175, P0172 After Multiple Repairs - What Could Be Causing This?

I own a 2018 Ram 2500 with a 6.4L V8 engine and am currently stuck with persistent OBD2 fault codes: P0300 (random misfire), P0175 (rich mixture bank 1), and P0172 (rich mixture bank 2). The vehicle has been through extensive repairs including thermostat replacement, coolant flush, water pump replacement, new intake components (short runner valve, purge valve), fresh spark plugs and coils, oil pan gasket replacements (twice), and full fluid system checks. I've also verified that the timing marks are correct, oil pressure is within range, and all sensors (MAP, crank, cam, oil pressure) are functioning properly. After a catastrophic breakdown on highway following a thermostat change, I rebuilt the engine with new components hoping to resolve the issue — but now I'm back at square one. All oxygen sensors have been replaced, EGR valve cleaned, and the vehicle runs smoothly under load. However, the misfire and rich mixture codes persist. I have a good diagnostic tool and am actively reviewing live data, though I’m not an expert in real-time sensor readings. At 199,330 miles, this truck is primarily used for long highway drives with heavy loads (concrete finisher work). I'm wondering if there's something I've missed — perhaps a fuel delivery issue, clogged injectors, or a vacuum leak? Any insights from experienced Ram owners or mechanics would be greatly appreciated. I’m not looking for a quick fix — just clarity on what could be causing these persistent codes in this specific engine setup.