What is your mechanism for halting the evaporation of microscopic black holes? Hawking radiation is a well-established result from QFT on curved spacetimes ("semiclassical quantum gravity"), and if you have a rebuttal of Hawking radiation that in itself should make waves in theoretical physics.

The issue is that when the black hole becomes small enough that semiclassical approximations don't hold any longer it could be that either the black hole becomes unstable to dacay into photons, or that a "smallest" black hole state is obtained. This would be like a new elementary particle - it has even been suggested that elementary particles are actually microscopic black holes.

Thinking about this, another question that arises is whether a stable microscopic black hole can accrete matter faster than it radiates it back as Hawking radiation. Remember that Hawking radiation is more intense the smallest the black hole. It's possible that matter around Earth is not dense enough for a microscopic black hole to accrete and grow.

We have met the enemy, and he is us — Pogo