Power supply buzzing, LED strip insulation has almost turned black
Could the LED strip turn black because of normal use/heat or should I have a better look at the power supply?


Yes, it can. Cheap plastic can warp and discolor under summer weather, and will do so faster when it has trapped the heat of the led and the FPC the strip is made of. Frankly. I've had cheap waterproof led strip yellow in room temperature over time.

The power supply can definitely be suspect as well. Without at least a multimeter. You cannot tell if it is under or over voltage, if it is stable, etc. Keep in mind that you can drive these led strips at more than 12V, up to 15V and they will work, at a significantly lower life time.

As to the wiring, unless there is a short, that's not too much of an issue.