A block similar to beacon or conduit for preventing mob spawns

The large area of the new caves makes it significantly harder to light up the entire area and preventing mob spawns even with the new additions to light mechanics. Something that works similar to a beacon or conduit that prevents mobs in a certain radius from spawning could be useful also for people who want to have darker more moody builds while not having to worry about unwanted mobs everywhere. I don't know how to balance it much more than limiting the radius and having it require resources like ore blocks for beacons and prismarine rings for conduits. Possibly having the block act like a "beam" and the effect stops applying past any points a wall so it won't light up entire caves just large open areas.