We use our traeger grill to do our briskets.

marinade/season first, at least four hours, overnight works best for me, I believe you don’t want a complex multi flavor marinade/rub, just the basic flavors, brisket has a excellent beefy flavor that you don’t want to cover up with heavy smokes, or seasonings, I prefer hickory, or pecan pellets.
i like to warm the grill up to max temp, put the brisket in once the grill is at 375-400° for about 20 minutes, turn it down to smoke for a couple hours, then back up to about 225° until it hits about 175-180° meat temp, then make a boat (bottom is water tight, you’ll end up wrapping the whole thing) and add in a couple cups of beef broth or something similar, wrap it up, turn the temp up to 275-300° Cook until the meat hits 205-210°. Take it off and let rest for about 20 minutes, slice across grain.

I actually prefer to take it off at a lower temp, to me cooking it to 210 meat temp gives the meat a rendered tallow taste, that I dislike.
I prefer to take it off at 190-200° But sometimes it’ll be alittle tougher than taking it all the way to 210°.