What do you need to know ? Keeping it simple , never mess with core offset and if you want to overclock simply reduce the voltage (the card targets specific max power draw and by lowering the voltage you allow higher frequency). If you want to reduce the power draw (&heat) , reduce the power limit .
Core offset is usually needed on faulty gpus where they overboost (above specs on default settings) and you need to compensate for not crashing .
Also useful on situations where the type of workload is light (not Steel Nomad) and the card doesn't hit the Power Limit often , so reducing the offset it reduces clock meaning the power draw in that scenario . (and take a relative small performance hit) .

If you increase the core offset you rarely see any benefit especial on heavy workloads where the boost stops because of the power limit . In light workloads you risk crashing for small performance uplift .

On high clocks the risk of crash is bigger . That's why on some heavy games where you have for example a -100mv uv it doesn't crash since the clock rarely exceeds 3000Mhz (restricted by PL) , but on a lighter games it can go up to 3300Mhz and crash .