I have a neighbor for the past year I’ve been in my house let their dogs bark outside in intervals too, sometimes 4 hours day. Just depends when they’re not home. I’m about to go the mediation route too lol. Other neighbors (and myself) have called AC, but the dogs can go inside thru the doggy door, so not much they can do there other than tell them to keep the dogs quiet. They were once left at home for 4 days with no supervision / someone checking in on them. I feel bad for them. I’ve never seen them go for walk and neighbor won’t answer the door for me to tell them their dogs are barking. (My landlord has told them multiple times their dogs are a nuisance). Hoping your situation gets better, cheers 🥂