Unfortunately, it doesn’t matter what you give them or what you do, but some dogs will always be terrified of the noise of fireworks.
Our previous dog was one of them, she shivered and shook at even the most far away noise despite all kinds of tranquillisers from the vet.
Our current dog sleeps through it all, maybe lifts his head occasionally, looks at us, and then goes back to sleep.
It is very distressing isn’t it Choux but I really don’t think there’s an answer for some dogs, it’s just the way they’re made unfortunately.