Nevertheless, this is a good indicator that the MB is probably at the root of your problems--at the very least.
The left-hand cable appears to be either a fan hub power supply cable, or a cooling pump power supply cable. Neither would connect between the SATA power supply connector (from the PSU) to any motherboard header.
The right-hand cable appears to be a PWM supply cable, which could connect between a motherboard PWM output header to either a cooling pump, or fan hub PWM input.
Connecting either cable between the motherboard PWM output header and any power supply output connector, would definitely destroy motherboard circuitry or PC board traces.