Have an option in Premiere to load in a document (e.g a word document) which then completes the captions based on line by line.

Example: I have a transcript in word, I edit it so the lines are of a suitable length for captions.
I then load it into premiere, it reads the lines and loads them in as captions, with each line an individual caption piece.

Ultimate version would have a function where you listen along and press a button to mark where the next line should start and premiere auto adjusts the captions to fit.