DSC automatically gets kicked in once HDMI devices starts to ask for more data then possible with uncompressed. Next gen consoles will still be locked to 4K@12Hz0/8K@60Hz because of chipset limitation. 8K@120Hz will be probably possible with the next-next gen. Separate from DSC, HDMI 2.1 chipsets also have their own compression to keep 4K@120/8K60 data under control.