> In the current times you’re either an agent manager or you’re in for a surprise.

This opinion seems to be popular, if only in this forum and not in general.

What I do not understand is this;

  In order to use LLM's to generate code, the engineer
  has to understand the problem sufficient enough to
  formulate prompt(s) to use in order to get usable
  output (code).  Assuming the engineer has this level
  of understanding along with knowledge of the target
  programming language and libraries used, how is using
  LLM code generation anything more than a typing saver?

The point is an engineering manager is using software engineers as typing savers, too. LLMs are, for now, still on an exponential curve of capability on some measures (e.g. task duration with 50% completion chance is doubling every ~7 months) and you absolutely must understand the paradigm shift that will be forced upon you in a few years or you'll have a bad time. Understanding non-critical code paths at all times will simply be pointless; you'll want to make sure test coverage is good and actually test the requirements, etc.