solved! Text::Wrap had the same effect as using \s instead of \b - the words wrapped but it was still half the width that it was supposed to be and it ate empty lines (I'm guessing there is some option to disable that, but as a quick one-statement stream filter I was looking for a short solution). Using -C however made the regex work exactly as it should have, with the correct widths and everything:

Using -C with Text::Wrap made the column width correct but it still converted \n\n to \n, which impaired readability. \b also worked properly with the wide characters but it split on periods and other attached punctuation. Thanks for such promt help!