Not necessarily. That is only the case for black holes with no charge and angular momentum. Given high enough charge and angular momentum for a given mass, blac

Not necessarily. That is only the case for black holes with no charge and angular momentum. Given high enough charge and angular momentum for a given mass, black holes become "extremal" and their hawking radiation/temperature approaches zero. It's argued these are unstable or maybe can't even exist for various reasons, but it's a pretty active area of physics AFAICT https://www.quantamagazine.org/mathematicians-prove-hawking-wrong-about-extremal-black-holes-20240821/ https://www.quantamagazine.org/mathematicians-prove-hawking-... That said, if these were primordial I'd expect their charges to not all be 0, so they'd interact with normal matter.