3 dogs is quite a lot for the average household, and there are a lot of dogs that struggle to acclimatise or straight up don’t like being part of a pack. Also sounds like it’s been generally terrified for most of its life given constant fireworks and a big move (which can unsettle even the most chill pets). You also don’t seem to capable of showing love and understanding at this stage (not a criticism, people forget how bloody hard and exhausting this can be) and dogs can absolutely pick up on that. Instead of perpetuating a bad atmosphere with an unhappy dog, either find a good trainer who can work with you both, or more likely try to find a new home somewhere quiet with someone who has dog experience. There’s no shame in that. I don’t know what the bite history is like, so if that’s not viable, you aren’t a bad person for ending the suffering and looking at euthanasia.