You might want to do a 1/4 batch and change just one thing, see how that works and if it's not enough, move on to the next option.

Simplest would be to reduce or totally eliminate the sugar. That would definitely increase the sharpness.

Next, if that's not enough, increase vinegar and reduce distilled water.

A final option would be to add acid, i.e. citric acid (sour salt).

Carol

I'm wondering how much water it takes to top off the jar ... if it's more than 2 2/3 cups water (a 50/50 mix), it might be as simple as being sure you use at least as much winegar as water ... I premix the vinegar and water to make it easy to get it even.
kay

Yes, increase the distilled vinegar and reduce the sugar. For dills, I don't add any sweeteners of any kind. The only ones that get sweet are bread and butters, and sweet mixed, or if I want a milder, less acidic flavor. Many times, I don't add any water whatsoever.