Bar geo

A bar with shorter width and reasonably tall rise. However, bar geometry wouldn't normally be something you'd look to for setting up something twitchy. Look for either a shorter reach stem, forks with different offsets, and, if you have the money, a frame with a steep headtube angle.

Sweep won't affect how twitchy your bike will feel.
It's all personal preference when it comes to bars. I personally find narrow, lowish bars more responsive and more comfortable. But most people disagree

Tall bars are less responsive

Straight Guage tubing and rise is all the matter imo , dropped over a bill to try 4 degrees upsweep compared to 1.5 and didn't notice fuck all but the stiffer feel of the SG tubing

That depends on the gauge of the tubing, thin straight gauge tubing will flex more than multi butted tubing. 4 piece are generally stiffer though.
I personally can't ride bars with less than 3 degree upsweep, and I like a fair bit of back sweep. I find it a lot more comfortable.