Sarcasm comes across much better in person than via text, which I’m sure you agree with.
I completely disagree. Body language betrays your sarcasm much more easily in person. In text is where it's much easier to hide the meaning you are trying to convey and confuse your audience.
You don't write the opposite of what you mean. And Poe's law isn't a problem to be combatted, it's a gift.