One thing that would be important to not is that creating a blackhole on earth (specifically a small one) would become extremely volatile as they shed mass in a form of energy; meaning a black hole of 1 kg would explode with nearly 90,000,000,000 J of energy assuming you could isolate it from all matter and prevent it from growing. This is due to the energy mass equivalence (E=mc²), and hawking radiation. The second big problem with making a portal from a single black hole is that the tear in spacetime would be random and we wouldnt be able to control where it goes but if you could hypothetically use 2 backholes and connect them the you would have a wormhole through space-time.

I am not trying make this seem incorrect as the read was interesting, I just wanted to bring in the context of the potential for trying to make a blackhole on earth would be extremely dangerous and difficult. Anyways the read was good and worthwhile.