Use of article after 'my career as' [closed]
Solution 1:
You've correctly identified the distinction at the end of the question. It's essentially the same as choosing whether to use 'a' or 'the' in general; the 'the' cases you cite both refer to a specific singular role, whereas the first few are one of many interchangeable role-holders.
It's worth noting it isn't strictly broken down by job title. We can refer to "my career as the chief nurse" (at Example Hospital), but it's just as grammatically valid to say "my career as a chief nurse" if we're referring to a series of chief nurse roles in different hospitals.