SIMPLE ANSWER: Ummm… maybe?
MORE INFORMATIVE ANSWER:
The goal of After is to mix fantasy with sci-fi futuristic elements. The background of this setting is recovering from a future apocalypse where most of our modern day technology was already obsolete.
So few even know there was a Cataclysm before the Dra’ken and Kord’emuri appeared. Their arrival ushered in the darkest age. For now, the eye of that storm seems to have passed. Death still waits outside for adventurers and explorers who think the wilds can be tamed again. While it is evident to those that have survived that the world is quieter than it was two generations ago, High Fantasy this is not.
It is a time of Warlords, Slavers, Wastkeen Raids, Tribes, and rediscovery of what was lost in the darkest age. Global communication has been jammed, and dangerous creatures are everywhere stunting any attempts at mass travel and recolonization. Surely there are remote Islands and other isolated areas where peace and tranquility might be found even leading to a sense that a Cataclysm never came at all.
Your area of the world may have a sense of High Adventure, for now… but, it is just a matter of time till the Dra’ken and Kord’emuri frenzy, again overpopulating and devouring as they go leading again to the horrors the past decades told of. Even if the swarms remain in the shadows, the Wastkeen raiders crazed and mutated by their Reyth water addiction are quite vile and their “Shamans” even more so as they play with magic and let it burn and twist them into horribly unrecognizable monsters.
So, is After a horror setting for 5e? Maybe… It really is up to you. Will you attempt to rebuild civilization, conquering the wilds while exploring what remains of the previous age, or tumble blindly into a den of death. After provides a few ideas, but this is your story to tell.