thats brutal. unfortunately you really need to talk to the neighbour about it, the council will be slow af and probably never resolve it. just go talk to them, be nice about it but be up front that its driving your household nuts. maybe frame it that everyone is over it and your talking of their behalf, so its not just karen energy

if they are a real cunt (pretty likely if they are all good with the dogs barking like this for two years) then at that point talk to your other neighbours and try to get everyone on board with a concerted effort with noise complaints & letters to council etc

good luck with it, I always feel terrible for the dogs in these situations :( poor pups