This doesn’t affect warranty I’m pretty sure and there’s nothing to “unlock”
The radiator can dissipate much more heat than 28W specified, the bottleneck is the thermal interface. All these “high temp at low load”, “uneven CPU thermals”, etc etc are the result of (relatively) low conductivity from CPU to heat pipe. At a given CPU temperature, the hotter the radiator (heated by the CPU)the better the cooling efficiency.