Kona "white" is the whitest white. Moda has a Super White Bella #436 that is so white, it's almost blue. Next is Bella #97 Bleached White pfd (prepared for dying). Then Bella #98 White Bleached is next in line.
You can go to
https://www.robertkaufman.com/fabric...age=5#products and
https://my.modafabrics.com/shop/sear...chType=keyword to compare.