It's a great quote though I am hardly a fan of Keynes. Quite the opposite.

Timing the market is near impossible, but often near enough is good enough and it's better to be too early than too late....

I don't Short stocks as a rule, nor Cryptos for that matter. The closest I would come would be options or warrants with some effective stop loss protection, but you don't need financial derivatives to be an effective Contrarian.