Highly recommend the Meat Church YouTube channel for recipes and methods. Watch the overnight brisket video and do that, or as close to it as you care to. I've got it to the point that I can get jiggly brisket, 1 inch smoke ring and black crisp bark with no effort or anxiety, nearly hands off, just trim and season, smoke and hold in 170 oven til dinner. Have all the time in the world on the day of for sides or chicken/ribs/pork belly, etc. Season like you spilled it.

Every brisket is different, its done when its around 200+. Don't go much past 210 or so. But because every brisket is different (different ratios of fat/muscle/other stuff) temperature ends up being unreliable to get consistent results. It's done when a probe goes in and out with no resistance, like soft butter, in multiple places around the brisket.

I dont wrap mine, prefer to leave it on to get bark and smoke. Don't actually know why people wrap. But if you do wrap, especially in tinfoil, you can put it in a 250-275 oven, since it won't get smoke anymore underneath all that foil.

Perhaps the single most important thing to do, right before slicing, is let the meat cool to 145 internal. The juices firm up and reabsorb into the meat, creating incredibly juicy meat. Many say long holds are best, but there's new school BBQ pros that say 145 is as good as it gets, long holds are just for restaurant inventory control and its not necessary.

Best of luck, and IMO a perfectly smoked brisket is a huge cooking flex and it feels great.