Low point of Arc
There are several factors that can influence where your swing arc bottoms out.
The position of the sternum.
The low point of your arc is broadly speaking going to be underneath your sternum. The other factors listed below will have significant influence but if you are leaning significantly backwards (or forwards of the ball at impact then that is where you will bottom out.
Shaft angle at impact
If the club is leaning forwards at impact it will be moving downwards and therefore, bottom out after that point. If we try and lift the ball by adding loft through the hit then the shaft will be leant backwards and the low point will be behind the ball. Thus, either hitting the ground first or hitting the ball half way up.
Ball position in the stance.
This won't directly affect your low point but will obviously influence where the low point is in relation to the ball. You can play the ball back in the stance to raise your chances of getting the low point past the ball but you will likely hit it very low and struggle with the longer clubs.
Assuming that our movements self-organise around our intentions for impact (see end point funnelling) this is a really important topic that needs to be prioritised in your movement representations (hierarchy of swing concepts).
Intentions of a low ball flight
If one is trying to hit the ball in the air then the corresponding swing movements will not get the low point past the ball. Conversely, if your intentions are to drill the ball forwards or and keep it down then will incite a more desirable set of movements that create optimal impact alignment.