Territorial reactivity is getting worse - what meds helped your dog?

I have a 2 year old supermutt 80 pound dog that is extremely territorial of our property and loses his mind barking at any sound he hears outside (or inside if it’s an unfamiliar sound to him). It’s particularly bad when he sees someone walking outside or an animal outside (we have a ton of deer in the neighborhood), and in those situations it has gotten to the point now where he slams himself into the windows barking like crazy the second he spots them or a car outside. He goes 0 to 60 and will be napping one second and then booming barking the next. We’ve been consistently working with him on positive reinforcement and counter conditioning but it keeps getting worse as he gets older. We live in a quiet neighborhood but obviously we still get a decent amount of people walking around and coming and going in their cars all day. Ironically, he loves when people actually come in the house and greets any guest with a wagging tail and a toy in his mouth, so I don’t really understand why he freaks out so much.

He’s been prescribed trazodone twice a day for a few months now since the vet wanted to see if that could be a shorter term fix to help us get through to him with training. At first it was working well but now some days it’s not helping at all, or he’s just super sleepy with no healthy in between.

For anyone with a similar dog, has Prozac helped? Going back to the vet in 2 weeks and based on our last convo, that will be the next med we try out. Just wondering if anyone had success with Prozac after a not wonderful experience with trazodone, or any other med for more long term management of anxiety. He seems so on edge all the time and I just want him to be able to relax again 😭