There's not a single author that absolutely everyone would agree is good.
I write fortunes for Chinese cookies.
All these numbers are good: 12, 43, 95, 8
I think we all can agree.
It would have to be a literary author that nevertheless is accessible to people not into literary authors. I say that not because I'm a literary snob, but because literary snobs exist and would not agree on genre authors. Steinbeck is a good choice. My pick would be Leo Tolstoy.
Kurt Vonnegut . Even if it’s only for Slaughterhouse Five I’ll accept that . I personally love his other books but I think one really good book can put you in the list
Margaret Atwood. I don't expect everyone to like her style but I think she's an objectively good writer.
I can't imagine anyone would dislike Mark Twain.
I think we can all agree that Dan Brown is a great author. It's really his incredible writing style. I get so lost in his prose and imagery that I almost forget that I'm reading a nuanced and subtle story, simmering and rising gently to a rolling and profound boil.
Tana French? Donna Tartt? Celeste Ng? Ann Patchett? Nathan Hill? Vikram Seth?
Edit: ooh and I love Georgette Heyer's regency novels too.