Apple

Correct. That's why I go back and listen to mine and then write down whatever it was that I needed to remember or do. Most of the time it's just me rambling and I only need to write down a minimal amount. (I have a 80 minute commute.)

When I want something to be text on my calendar, I press my Carplay button for Siri to begin listening and say "Add a Reminder to do such and such today" and it's fed directly into my calendar. (Reminders feed into the calendar I use automatically.)

Of course if you don't use Reminders that way, you can also say "Remind me to do such and such at a specific date and time." Then you'll get a Reminder for that. I find that to be helpful too.