I would settle for people and software just not doing that '06:00pm' type abomination. 6pm fine, 1800 fine (06/6am fine) but not 06pm.

PM is like ROT12 AM.

Many years ago I committed to setting everything to 24hr clocks. Even when I still had a standalone digital alarm clock that plugged into the wall; in fact that was the impetus to change.

Because it was very easy to miss a little "PM" pip in the corner, when reading or setting the time; and setting an alarm depended on getting the pip correct, so eliminating the pip for me meant eliminating ambiguity in the digits.

It's been a fairly successful transition, although sometimes I look at "16:15" and think it's 6pm so the "mentally subtracting 12" needs practice. And there are still special snowflake UI widgets that ignore my i18n settings, and constrain how I enter or specify a time.