"Send Later" functionality in…
"Send Later" functionality in Mail and Messages are both (according to Apple's documentation) completely client-side. That being the case, why does it support iMessage conversations and not SMS/RCS ones?
Then you're in luck, because you'll pay $0 for my 2¢ when you subscribe to my work, whether via RSS or your favorite social network.
I also have a monthly newsletter where I write high-tempo, thought-provoking essays about life, in case that's more your speed:
And if you'd rather give your eyes a rest and your ears a workout, might I suggest my long-form solo podcast, Breaking Change? Odd are, you haven't heard anything quite like it.