A dog next door can -sometimes- be silenced by an anti-barking device, but there should be minimal obstacles twixt device and dog. Basically, the device is activated when the dog barks. If there are barriers then neither the dog will properly hear the device ,nor will the device "hear" the barking. Indeed, the device can go off even when the dog is silent but a loud car passes by. Unfair on old Spot.
There are devices that constantly emit an uncomfortable sound but all this does is prevent the dog coming too close to the device . If the dog is constantly in a small garden next door , and therefore cannot escape the sound then all the device will do is drive the dog crazy -which is fine if it shuts the mutt up, but may actually cause more barking. (These devices are more effective on small children ,especially on a sunny afternoon when they're all noisily out on their bouncing castles.)
But the real problem in OP's situation is the multiplicity of dogs at varying distances. One can't silence all of them, other than by stalking the gardens at night chucking poisonous tit-bits over the fences. No device can silence, say, ten dogs over a few hundred square yards, other than a bomb.
Writing to animal welfare groups,lawyers etc may work with one dog-owner. But if there are several such owners nearby then such letters will produce few results other than OP getting beaten up by the irate dog owners.
Remember that many dog-owners regard their incessantly barking, publicly defecating, child-biting hounds with more affection than normal humans have for their children. Any criticism directed towards the brute and their (often more brutish) owners will elicit a response that may make the torturous noise of the creatures' barking seem pleasurable in comparison.
Once there is a mass of dogs in a small area then the only way to escape the canine cacophony is to escape that small area for good.