What I sometimes do is use the brake to lock the rear and initiate the rotation (slide, oversteer, etc.) towards the apex while using throttle to stop or control the lock-up. I think of it like yaw in an airplane – you’re literally controlling the yaw of the kart by balancing the brake and throttle pedals. Having the throttle applied also raises the revs earlier.
I find the technique works better in some formulas than others. Also, you have to be careful not to nullify the braking with the throttle. Anytime you overlap throttle and brake you’re reducing the braking efficiency.
Also for the most part, oversteer is generally considered to be slower. So the technique is best right just before the transition from braking to throttle. So the rotation is happening right about this transition. And by rotation, I mean the kart is physically rotating around its center point independent of the line you’re taking.