@dardan Sounds like she probably looks like a pit bull mix even if she doesn't have a pit bull breed as her main breed. Not especially easy to rehome an adolescent pit-looking mutt with reactivity, to be honest.
If she legitimately has a significant content of Lab, you might be able to get a Lab rescue to take her. Especially if you can show them the DNA test (a lot of breed rescues near me have been getting burned lately so they won't take ambiguous dogs they can't verify the breed of). Real lab mixes from breed rescues are in higher demand than shelter "lab mixes" (pit bulls) which is what she'll be perceived as.
I would focus on the Lab rescues because they have higher demand and lower supply. American Bulldog rescues in some areas are inundated with dogs (that are and aren't real American Bulldogs). While they're still worth contacting, I'd prioritize Lab rescues.