Can I get solo legal custody if the kids’ father never visited the kids in the past 2 years, and never followed the court order visitation?

The kids never spend more than 4 hours total in the past 5 years. By court order, we moved. After 1 year, I got job in another state and moved with the kids but the kids’ dad don't know that as he never visited or know anything about the kids. He sent a couple of messages here and there, he pay child support, but no other contact, no phone calls and he does not know how they look like. He refused to get passport for the kids as I have to travel with my job and now there is a chance they will fire me if I don't follow traveling job. Thank you.