MacBook – New Macbook Pro 2019 has high temperature with low CPU usage

The current lineup runs CPU up to 100 C. Is is normal, so you might be able to get something ike SMC fan control to ramp up the fans earlier, but since the CPU clock rate can over heat the blowers, you might not be able to do anything short of externally cooling the case significantly.

Both the clock rate and fans work in conjunction, so upping the fans in turn lowers the clock rate restriction - canceling your efforts to alter the designed behavior.

The thing is that 100% CPU usage refers to a single one of the cores in your CPU being fully loaded (or an equivalent load distributed among all the cores). I assume your MacBook Pro has a dual core CPU with HyperThreading; that's 2 physical cores plus 2 logical cores exposed by HyperThreading. Thus, you could in theory achieve as high as 400% CPU usage (4 cores times 100% each).

As to whether it is sustainable, in principle it should be, if the cooling system is in order and the cooling vents are not clogged with dust or blocked by any objects. Even if it's not and you reach supposedly dangerous temperatures, the CPU should throttle itself to prevent any damage.