.element {
  filter: blur(2px) grayscale(80%) contrast(200%);
}

All three of those filters will apply. But somehow I never thought about applying the same filter more than once. That also works, and they don’t override each other, they “stack” (or whatever you want to call it).

So here’s some useless bar trivia for you. What is blurrier, filter: blur(2px) or filter: blur(1px) blur(1px)? Answer.