I think the largest square you would want to go to is 10" finished. This would allow you, theoretically at least, to cut 4 10.5" squares across the width of the fabric (four times 10.5 = 42"). Two yards of fabric would equal a length of 72", so you could (theoretically) cut 7 sets of those squares. This means you could get 28 squares out of each fabric.
There are 4 fabrics, so (theoretically) you could cut a total of 112 squares of 10.5".
I say theoretically about all this because, if the fabrics were not cut straight, squaring up might cause you to lose an inch somewhere that would prevent a cutting that is 10.5" wide.
With 112 squares, you can do a layout of 10 x 12. Since the finished size of the squares is 10", this would result in a quilt of size 100" x 120". According to
https://suzyquilts.com/quilt-sizes-chart/ , a king size quilt would be 110" x 108". If you change the layout to 11 x 11, you would end up with a quilt 110" x 110".
So, you could *barely* squeak out a king size quilt from this amount of fabric. It would not be a large king size. And, if even one fabric was cut crooked, you won't have enough for a king size.
I started with large 10" squares because less fabric is used up in seam allowances than with smaller squares. I might try re-calculating with 5" squares to see how that works out.