Never once used an agent in over 60 years of visiting, living, working and now in retirement in Thailand. However, as age catches up with me, I will likely need to do so at some stage. Currently 82 years old.
If you continue with this you're going to create a lot of trouble for all of us. Pay your taxes on the basis of your own situation, and leaveus to do the same.
In over 60 years I have never had a problem anywhere in Thailand with dogs. I am totally opposed to any form of 'eradication'. The OP says he has PTSD because of dogs. He needs to see a doctor specializing in mental health issues.
I would definitely suggest a trial run, an extended holiday, before committing to this. The last thing you want is to bring them here on a permanent basis only to find that they don't like it.