In this 2 txt files, There content were looking alike, my first thought was to quickly compare them and, yes, they were exactly the same with some exceptions, using a txt compare tool I got this result (the differences are highlighted in blue):

It's a bit zoomed in, but you can see one text file on the left and the other on the right. Knowing the flag format is ZiTF{flag}, I figured out that you need to alternate characters—taking one from the left text file, then one from the right, and so on.