If you haven't done it in a couple years, overclocking is a bit different now. I had similar confusion with my 6700K.
First turn off all the power saving stuff, speedstep, E1C, etc. It will screw you up, as it's rather tricky to get working properly with an overclock. Once that's off, set a 45x static multiplier in the BIOS. Burn-in at the highest multiplier you can, trying 46 then 47, etc, get it stable, then you turn the power saving stuff back on and get it to work properly (which is not trivial).
You will almost certainly have to increase the TDP ceiling and voltage in your BIOS to hit 5Ghz. Turning on vCore loadline calibration will help as well to counteract droop in the vCore.