Keep in mind that the coolant at a temperature of 100C is right at the boiling point of water at atmospheric pressure. Other metal parts of the engine will be hotter in normal operation.

Engine oil is expected to run about 100C so that moisture will boil away, so the valve cover will be at 80C or so.

Heat under the hood is normal, and as human beings we are always impressed with normal underhood temperatures, since we cannot relate to them properly in our normal skin...

Best Regards,
Jim