Finally, a use for Buffy's Swearing Keyboard.

Or possibly the exact opposite of that, I can't tell if it's a one-to-one mapping on mobile: https://www2.b3ta.com/buffyswear/

(Also, I'm feeling my age now, given how many years have elapsed since that kind of thing passed for internet culture…)

Because the real data stream would still be there, just mixed with some noise. It feels harder to analyze whether the noise sufficiently obscures the real keystrokes than it does to ensure the actual keystrokes reveal no information.