an additive material. you make the texture a greyscale. you should push it thru photoshop contrast filters to remove all the remains of blue shading in it. you can compress it as an alpha. do a bit of shader math and set the blendmode to additive. and there you have it. it costs a lil bit more in terms of “shader complexity” or just overdraw, but it does not emit light into the lumen scene, and hence does not emission flicker.
