The problem with "Evil"
is that it's nowhere near dark enough for a show called "Evil". The team are all goody-two-shoes, the church is a benevolent institution, the demons scare a few people and then disappear never to bother anyone again. And how long can you keep up the "maybe magic, maybe mundane" trope for? It gets awfully predictable and unbelievable after a while.
Compare it with BBC's "Apparitions" for instance. A series I didn't particularly like either but at least it was gruesome, featured terrifying demons every episode which terrorised our priest hero by killing all of his friends, making him literally unable to pray, and forcing him to perform a black mass. The church is portrayed as a nest of corrupt vipers in league with the Devil himself (through email no less) all for their own personal gain.
Or, how about the excellent "Afterlife" with Leslie Sharp and Andrew Lincoln in which the characters own flaws kept them from working together and in which the ghosts were rarely defeated but often understood and their own stories were crushingly sad and relatable?