I don't know why this older camera looked SO much better (than the HERO7) initially. I think it may be due to excessive NR (Noise Reduction) on the HERO7. The way I worked around it on the 7 was to set the ISO MIN and ISO MAX to 200 (for some reason that produced less NR artifacts).

NOTE: I am in the process of working on a custom LUT for this camera, but the newer GoPro models will be my priority at this moment (I will get to it, though).