Do you need to overpower a Ki blast itself or its explosion to scale to it? If the latter, how are you supposed to overpower/punch an explosion?
So here's the thing with Ki blasts:
Ki is life energy. The more you have and the more you enhance it, the more you can output it and the stronger it will be. Warriors capable of using Ki typically spread it throughout their entire body so as to boost all of their physical abilities. But Ki users are capable of gathering specific quantities of Ki into a single point and firing it as a blast of varying strength. It seems that they can actually effect the power of their Ki blasts based on the technique itself (Kamehameha-Super Kamehameha, Final Flash>Galick Gun, etc.) but we don't know much detail on that.
So basically, if their entire body is enhanced to a level capable of destroying planets and going faster than light, a Ki blast technique will be on a somewhat higher level than that. It's based on the strength of their Ki, but there is a larger amount of it focused into one point contrary to how it's usually spread throughout their entire body. Of course they can also just focus extra Ki into one body part or other object to enhance it with the same effect as a Ki blast.
This is all best shown in Goku & Piccolo Vs. Raditz. We visually see that Raditz's scouter detects a large increase in power level when Goku and Piccolo use Ki blast's. Such a drastic increase that their Ki blasts can actually hurt Raditz despite their normal attacks having no effect. And the other attribute of certain techniques boosting the power of the blast is also shown. Goku being slightly stronger than Piccolo but his Kamehameha being far weaker than the Special Beam Cannon.
For a character to overpower a Ki blast, they generally just need to be sizably stronger than the user of the blast. Raditz stopped Goku's Kamehameha and tanked the explosion with only some moderate damage sustained to his hand, because he was much stronger than Goku, enough so that even a charged up Ki blast from him wasn't able to deal much damage.
At best a well-used Ki blast can make up for a difference of maybe 2-3x going off of power levels.
Edit: And I feel that I should emphasize that Ki amount and Ki strength are two different things. The Android's have infinite Ki, but they're far weaker than Goku. This is why even when a character is low on Ki, they can still keep up with an opponent they were on even terms with prior. Their Ki is still strong, but they don't have as much of it to continue enhancing themselves or use Ki blast's as powerful.