So thus far you have tried punishing the bark with nasty smells, punishing the bark with a nasty sound, punishing the bark with pain?
Punishing the bark isn't working, nor will it, because it does not address WHY he is barking, nor does it teach him to do anything as an alternative.
What training and mental exercise does your dog do?
I suggest scatter feeding twice a day and food dispensing toys several times a day.
Also, block his view of passing pedestrians/traffic/cats etc by using frosted window film on windows that offer such a tantalising and frustrating view.
Teach him that the door bell is a cue to go to his bed, its quite simple, because all your trained cues like 'sit/down/come' are simply sounds just like the doorbell is a sound.
Get a new remote doorbell, before you fix it to the door, pair the sound with the action of sitting in his bed, so you ring the bell, chuck a treat in his bed, ring the bell, treat in the bed.. when he runs to his bed from no matter where he is when the bell sounds, you can start to increase the time between getting to his bed and getting the treat. When he can go there AND WAIT.. then fix the door bell to the door and instruct people to use it.
Meantime, stick a note on the door saying you are training your dog, and may take some time to answer the door -t his means you can stop rushing, ask the dog to go in his bed for a treat and answer the door calmly.. and all that reduces the stress and arousal that triggers barking.
You can also teach a bark on cue/shush on cue (you teach both at the same time with the treat presented almost UP his nose whilst you say SHHH.. very few dogs can sniff and eat a treat AND bark so he WILL shush (because he was barking because you asked him to) and eventually you can also use that to shut him up when necessary.
Dogs bark for a reason, unfortunately one of those reasons its that its enjoyable to do. You need to meet his needs, remove his stress AND ensure he has more enjoyable things to do than barking.
None of the punishment based gadgets or methods will achieve this.
Carry on down that route and you'll eventually need to give him a jolt off the mains electric to shut him up and that still won't work and likely will cause other behaviour problems to arise.
Stop punishing your dog for being a dog.
The behaviourist you saw... is not a behaviourist, was it bark busters? Chucking the discs simply interrupts the barking, pairing the discs with the removal of reward is how they are meant to be used... and is a devastating psychologically damaging experience for many dogs, hopefully you didn't do that.