I think this promises to be a very interesting thread.
I spent my career solving wave equation problems. In my case, elastic rather than electromagnetic, the impedance is pure real. But the change to complex impedances for EM is not a big deal. It's still the wave equation.
I bought Dunsmore's book and am extremely displeased with what I have read so far. I regard the TDR chapter as pure marketing FUD. Trivial first year graduate level Fourier transform homework problems are presented without solution except "buy our proprietary software". In fact, there is no explanation of what the figures show in many cases. That might be acceptable in an application note. It is not acceptable in an expensive monograph which purports to be authoritative.
A transmission line is the intro 1D seismic case before going on to the complex and difficult reality of 3D. I've written 1D codes as homework problems, written 2D anisotropic codes professionally and worked on 2D & 3D codes of a range of complexity and methods. The more I look into the VNA calibration problem the more disturbed I am with what I read. I now have a strong sense that some emperors have no clothes.
My training was in the classical mathematical physics tradition, so EE jargon and conventions are often confusing. I'm learning to make the translation, but it's still a struggle. So I'm likely to misunderstand things from time to time. All one can do is press on.
I shall have more to say later.