The Bohr model is incomplete and has drawbacks. But one thing is a mystery to me. Why did it so successfully calculate the Rydberg series with quite good number of correct digits?

Having such a good prediction one would expect that there exists an extension or modification to it, although we may not have found it, that would yield the correct model. But today we have abandon it completely and use QED. I would expect that from QED we should be able to derive the math in the Bohr model, my sub question is if there is such a derivation and it would also be super duper if we could sketch it here.

To reproduce the energy levels is not enough, that's too simple. What bugs my is that Bohr derives the energy from very few assumptions and sets up the solution through a natural force balance. Why is it that a faulty model can deduce the energy levels? My expectation is that the success to use this force balance should be possible to be answered from Shrödinger or Dirac and it is this link I want to know more about.