Is it possible to add a "blur" effect to a specific theme variable: I.E., 'var(--card-background-color)'

Is it possible to add a “blur” effect to a specific theme variable: I.E., ‘var(–card-background-color)’ either via card-mod or another way? I know that the blur effect is already available for the backdrop-filter.

I have the same question… hopefully someone has figured out a way?