I overlock my Gigabyte RTX 3060 12GB OC with MSI Afterburner, with Mem at +550, Core at +55, Voltage at 100%, temp limit at 90C and power limit at 124 (which are the highest possible for temp and power). I stress tested it with FurMark for over 30 minutes and the highest temp I’ve got is like 67-68C, on very rare occasions it reaches 69 (nice), I got a 70 once and never reach it again. I’ve read that overclocking reduces the GPU lifespan since it causes more stress and high temp. But mine is no where close to thermal limit so I wonder if overclocking is harmful to the card if the temp is below the thermal limit.
If you are happy with your clock settings then you can try reducing voltage in small steps until its unstable, then set voltage to last stable value or step higher. With lover voltage you get less heat and less power consuption