Is there a real physics theory behind Stein's Gate time travels?

I looked into it a bit and discovered that the idea of creating a time machine using Kerr black holes might not be completely random (even though it’s still purely theoretical).

In 1963, Roy Kerr found a solution to Einstein’s equations, the rotating black holes (the non-rotating ones were discovered way before in 1917 by Karl Schwartz while) Their rotation drags spacetime around with them (due to the enormous mass) creating an effect known as “frame dragging”, which creates a region called the ergosphere around the black hole.

In the mathematical extension of the Kerr solution, there are regions containing what are called “closed timelike curves” which, if you could travel along one of these, you could eventually return to an event in your own past (when you started riding that "space-time ring", meaning that you could actually travel through time.

Obviously it's completely impossible to build a black hole from a microwave and a cathode ray tube, but still interesting the physics behind the idea.

Does anyone know more about this?