It's hypothesized that "quantum" black holes may have formed during the big bang. In two sci-fi stories I've read, quantum black holes, when found, were artificially given an electric charge. In one story, it was previously used by an alien race, vibrated with external charges to produce a gravity wave beacon. The other is used by a pirate type along busy inter-stellar commerce lanes to produce an unexpected mass concentration, which destroyed faster-than-light space drives. He controls its position by its charge.
I contend that an electrically charged black hole is meaningless. A static charge is the equivalent of electromagnetic radiation at zero frequency. Therefore the charge wouldn't be observable.
We talk about light not being able to leave a black hole. I think this only applies to light that begins there, if such makes any sense. Light which enters the event horizon would orbit the center and emerge at another point, apparently gaining and losing frequency as it does so, since it can't change speed. It's questionable whether there would be anything inside to stop it or diminish it. Outside the event horizon, light would take a hyperbolic orbit, but perhaps anywhere inside it would be parabolic, a retro-reflector.