If the bottom hose is cool your radiator is most likely plugged up.
I had this same exact thing happen on my A2 Jetta. Inevitably, it blew the head gasket all to hell.
Also, try to avoid running the engine WOT while its still cold. All kinds of bad things can happen, including a cracked head.
That is the WOT?
The rad is fine I flushed it through when i emptied the system
Wide Open Throttle.
In your vid you posted, it looked like your temp gauge was still at the bottom of the scale.
That was taken ages ago - that was after about 25 miles of driving!