Using daisy chained cables are fine, especially on a GPU like the 3070 that's relatively power efficient and can only pull 250W to 300w max, of which only 200-250w would be probably be coming through the cables, and that's when power limited. Almost any modern aftermarket PSU will include at least 18 AWG cables that can safely handle 288w (8A per 12v wire) over a single cable at normal ambient temperatures. Now if you have a multi 12v rail PSU that's hitting OCP and shutting down due to transient spikes, or maybe instability, then you would want to consider individual cables, but once again, that would be very unlikely with a 3070, and at no time would the GPU be at risk. These ratings are for thermal runaway causing fires from pulling too much power, not for danger to the GPU or other components.