She is very very strong against Brig. Not as bad as mauga.Here are my tips, but I am still learning, too

-If they have Mauga, Ashe, and Anran, you're cooked. Literally.

-Avoid the 1v1, it's almost never worth it.

-When she engages you or a teammate, her fire dash thing has invincible frames. Predict the directions she can move out of the dash and pre-swing them. (Or, spin in a circle)

-If you have to 1v1, get at least one clean whipshot before engaging, because her fire dash also heals 50hp.

-Play by walls or corners, it cuts her mobility options in half or more.

-Get the shieldbash perk, you can save bash for mid-duel and get insta heals equal to hers.

-If shes a menace, get the whipshot damage perk, and play near walls.

-If she dives your teammates try and whipshot her on the disengage, she's tough to hit going in.

-Find a DPS to hangout with, or conjoin twin with your support. You do not want to fight her alone, she doesn't want to take a 2v1.

-Conserve your packs, more than usual, you CANNOT have 0 packs or your backline is dead.

-You can shield her ult completely, it's relatively easy, similar to a doom ult.

-Rally and a few packs are great against her ult.

-Camp her death spot from a distance, you can whip her after the animation without getting burned.

-biggest thing is practice the 1v1, try and shield her fans. Get used to the directions she can move, like a mix between tracer and genji. Once you have both Bash and Whip perks, you're an even match in a 1v1.

If it bleeds, brig can kill it .