The GM/Cadillac recommended 5W-30 oil for your car and engine gives perfectly satisfactory oil pressure.
Oil pressure is a function of bearing clearances, oil temperature (normally around 200 degrees F), engine rpm, and oil pump relief valve setting. Yes, there's an oil pressure regulator in the oil pump to prevent overpressure. There's also a bypass valve in the oil filter to prevent media damage due to cold oil or flow restriction (high viscosity oils). That valve sends straight, unfiltered oil to the engine during cold starts or maximum performance (high flow) operation.
Oil pressure is NOT lubrication and cooling - flow and volume are.
DEXOS is not a branded engine oil - it's a GM specification for minimum oil performance in a GM engine. Practically every name brand of engine oil on earth meets the DEXOS licensing specification. Some choose not to pay the licensing fees to GM.
My late 2016 show approximately 70 psi in start up and steadily drifts down as the engine warms up. After about 10 minutes of idle it hovers around 35 psi. After driving around for awhile and up to normal operating temperature, and while stopped at a light, the pressure is 20 psi. Hope this helps.