Compared to a lantern being in hand, when placed on a hip it's barely lights up environment.

Curios Lanterns does not handle dynamic lighting, it just adds the model and hip slot. Radiant Gear handles lighting for curio slots, however it only serves as a bridge Curios and your dynamic lighting mod. There is likely a conflict regarding your dynamic lighting mod and/or shaders, rather than Curios Lanterns or Radiant Gear.