Constantine. It had it's problems, like many Arrowverse shows at the time, but Matt Ryan was a fantastic John Constantine and I thought the show had a lot of untapped potential.
he has a fantastic run on Legends of Tomorrow, never seen the Constantine show as its not on any streaming I’m aware of so not sure how different the character is, but I imagine he plays it similarly. Legends itself is probably the best arrowverse show, after they get past the first season and stop taking it seriously.