That’s borderline impossible unless you have that grill absolutely cranked up. There’s no way that grill temp is accurate.

From 225-250 degrees it’ll be an hour to an hour and a half per pound to properly cook.

This particular brisket is probably not going to be very good and is a bit of a lost cause.

Get a new grill, (pellet smokers are the easiest), cook at 225 next time, and plan on 1-1.5 hours per pound and time it as such for meal time.

Also: aim for 203 degrees, not 200. I’ve cooked a ton of briskets and I’ve determined for me that’s the best temp.

Do the probe test at 203. If it slides in and out like warmed up butter: pull, let rest at least an hour, and you’re done.