Ugly banding on black texture

I can't seem to get rid of this. I exported it as a 32 bit floating point precision .dds file with DXT5 compression and mipmaps with GIMP. As far as I understand some of the banding is caused by the limitations of LCD screens but I'm pretty sure this is software related because it doesn't look like this in GIMP and exporting it from Sims 4 studio has it have significantly worse quality than the original.




EDIT: Managed to get around it sort of, though DXT5 compression does make it hard.