I would love to be able to select (and view) times in a 12-hour format. Currently, we can use the Quick Add Magic to input a due date in a 12-hour format, but (as far as I can find) there is no way to view it again in that format. I’ve seen this post which mentions that it should be a thing by default based on either browser locales, or language, but my language is set as English, and as far as I can tell so are the locales in my browser.
I would imagine this would simply be the addition of a AM/PM drop-down next to the time selection, and reformatting the hour based on what was selected.
Welcome! 
This is actually planned, but low priority. Happy to take PRs for this.