Grace is directly related with the Erdtree and it’s bountiful age.

Grace is linked to Marika.

You know that the Tarnished only exists as part of a plot set in motion by Marika long ago, right?

In Marika's own words.

My Lord, and thy warriors. I divest each of thee of thy grace.

With thine eyes dimmed, ye will be driven from the Lands Between.

Ye will wage war in a land afar, where ye will live, and die.

Then, after thy death, I will give back what I once claimed.

Return to the Lands Between, wage war, and brandish the Elden Ring.

Grow strong in the face of death. Warriors of my lord. Lord Godfrey.

She stripped Godfrey and his warriors of grace so that they could continue to struggle outside the Lands Between and grow stronger for the time she would shatter the Elden Ring.

And when that time came, the dead warriors outside the Lands Between were granted their grace back, resurrected and guided to the Lands Between to brandish the Elden Ring.

The tarnished are essential to that plot. The tarnished exists as a result of that plot.

Also, I’m saying this again, but you yourself posted a dialogue of a character (Varre) asking the player IF they are familiar with grace or not.

You keep repeating this as if it's a good point when it really isn't. You're fixating on a point that doesn't matter because I don't claim that our character if they're familiar with it or not.

Varré immediately follows up with the fact of being a tarnished.

Are you familiar with grace? The golden light that gives life to you Tarnished.

You may also behold its golden rays pointing in a particular direction at times.

That is the guidance of grace. The path that a Tarnished must travel.

Whether you're familiar with grace or not doesn't matter. He doesn't posit it as not knowing whether you have it or not, he follows up with what naturally assumes you have it if you're tarnished.