The value returned in cell $19$ is a whole number. You want to display the weekday equivalent.

In cell J$9,$ insert a VLOOKUP function to look up the value stored in cell $19,$ compare it to the array in the range $H2*16,$ and return the day of the week. Use mixed references to the table array. Copy the function from cell $Jg$ to the range J$10$:J$33.$