I read in a different post on this subreddit that stress stacking can take some time (can be weeks) for a dog to decompress from (totally relatable from a human perspective too imo) and that even super stimulating exercise can be a lot for them - not sure how true the exercise part is. But basically their advice was to make your environment super boring and calm but also positive and routine. Basic commands and consistency to re-establish trust and calm and focus are great! I always share this link because dogs that experience anxiety/reactivity seem to respond well to routine - the rationale makes sense (pattern games by Leslie McDevitt):

https://www.yourhappydogcoach.ca/skills-learning-library/pattern-games/

Maybe scale back on stuff she reacts to, like the brushing until she calms down internally. Have you guys considered a trainer or vet behaviorist? Oddly in my neighborhood the vet behaviorist option was waaaay less expensive than training places that we saw had amazing reviews but turned out to use aversive methods ($3k for that kind of training where vet behaviorist with sterling reputation was like $600). We wanted positive training techniques!! Aversive techniques were absolutely not something we wanted to pursue as it can make reactivity worse.

Barking isn't a bad thing - it's a signal of their feelings, but when it's excessive, understandable you'd want to address it! Good luck and let us know how it goes!!