If the final episode of the first season had a message. It is there is no going back for Nathan and Ava Bartlett.
As Matt tless them. 'This will never end.' It also has Matt yanking their chain.
He has deliberately left Ruby's body for Nathan and Ava to deal with.
Matt has killed again and will do so even more. Fresh content for the podcast, now with spin off potentials.
He has been in contact with other serial killers, so they can have their own podcasts. Just like American Idol. Matt is looking for serial killers with their own sad sob story.
It is clear that the serie his hoping for a renewal. So there is no proper resolution. Apart from Nathan and Ava do dispose of Ruby. It also seems that she was planning to contact the police and tell all.