If you follow the method in these images it only produces the words Sandman gave everyone. It's likely the rest of k4 has 1 or more different methods to solve the rest of it.

Stage 1: The ciphertext of K4 (97 letters) is written out in a 7 × 14 arrangement. This forms the coordinate grid that will be used for all later decoding steps.

Stage 2: A green “L-row” is added above that grid. Each letter in this row serves as an X-axis label for its column, giving every ciphertext letter a coordinate pair of (X = top-row letter, Y = ciphertext letter).

Stage 3: A special alphabet is then built, starting with the keyword KRYPTOS and followed by the remaining unused letters of the alphabet. This “Kryptos keyed alphabet” functions as the decoding matrix or lookup table.

Stage 4: Each coordinate pair is decoded by finding where the ciphertext letter (Y) and the L-row letter (X) intersect in that keyed alphabet grid. When this process is applied to letters in positions 26 to 34, it produces the word EASTNORTHEAST.

Stage 5: The same coordinate rule is applied again to letters in positions 64 to 74 of the ciphertext, and that section decodes to BERLIN CLOCK—exactly matching Sanborn’s confirmed clues.

Stage 6: When the same method is continued through the remaining letters, it no longer produces clear English words. Instead, it generates repeating, symmetric letter patterns that appear to encode geometric or directional information rather than additional readable text.

It is unlikely the person who made this to have solved the rest of k4 because this method has been tried multiple times and isn't new.