I have a 4690k! With thermal conductive paste mx-4! In idle state 22 degrees. In full load up to 47 degrees.

When the PC starts up, it begins to spin very quickly and makes a very loud noise, but after 4 seconds, the rotations start to decrease

After 5 years of operation, 1 out of 2 times it doesn't start. From the friction of rotation it has, it seems that the bearing of the shaft has worn out. Given that the system was not overheated (did not raise temperature) and the case was a large tower where there was another fan, I consider that 5 years is not enough, even for a fan of this price.