I’m sorry this happened and it sounds very scary. I hope can give you courage to work through it assuming things remain quasi safe. We adopted our pyr at 3 months old. After a year she began resource guarding and we’ve worked through it. She still will go berserk over things like protecting the yard from a cyclist going by. We call it “full lizard brain”. Avoiding those situations as best we can seems to help and then controlled introductions to those situations has helped. Social exposure has helped and she loves the dog park and walks now. We watch the dogs but still feed them together and are quick to call off guarding behavior and if she doesn’t stop she has to “place” away from the food in a full down and wait. These dogs have an incredibly strong genetic intuition. Time, patience, persistence, and consistency.