To fit better with the "naturally immune to the perils of the nether" part, maybe blazeborns interact with lava, like how normal players interact with water. For example: not taking fall damage when falling from great heights into it, or having better vision in it. This will make traversing the nether a bit less annoying while still being a challenge.

I agree with you, I tried to install torrid vision mod to improve vision under lava but it seems incompatible.