Diffusion filter

Diffusion scatters a small part of the light hitting the sensor, so bright points glow outward, contrast eases and skin texture softens. Tiffen's Black Pro-Mist is the filter most creators own, usually at 1/8 or 1/4 strength.

It caught on because modern cameras resolve in a way that can read as sterile, and glass puts some of that back without touching a grade. Two cautions come with it. The effect is baked into the recording and cannot be removed later, and pointing a heavily diffused lens at a bright window can turn a whole frame milky.