I like it that Apple's Calendar app now includes scheduled TODOs from Reminders.

I love checklists (early adopter and fan of Trello; sadly it's well past its peak), so Reminders is now a natural way to organise them. I can add a due date (and optionally, time), when I will get a notification. Overdue reminders still show up in the "today" view.

So for things like "lunch with a friend", I just set due date to whenever I should follow up, postpone until actually scheduled, and it continues to show up both in my reminders and in the calendar. It works for me.

As for the more free-form stuff, I keep a journal in Notes. I have a shortcut that looks for today's note in the "journal" folder, and if none is found, creates it; then it inserts the current timestamp. I can just start writing whatever comes to my mind.

Since the journal is already organised by date, I can always look back. I only wish I could run the shortcut straight from the Notes app.