SPOILERS FOR WN

Now I haven't read the LN so I can't point out the differences specifically but I can tell you what happens so far in the WN.

Before I started it I looked up which one to read and chose the WN because apparently the MC is a bit more cynical and because its fully translated.

Now at the end of Volume 4 in the WN I believe the revolt caused by Witch is stopped and she is sent to her death in the another city tortured to death by an infamous king. The Shield Hero is given land and begins to raise a loli slave army for defeating the phoenix. He eventually purchases Atlas and her brother and finds the rest of the heroes in a sorry state, bringing them to his town. They join his side, Atlas is cured, and from here on its him grinding for the boss. The fight of the Phoenix comes and its harder than expected eventually leading to Atlas's death when she protects The Shield Hero. After that is some depression, then recovery and back to grinding. He gets a personality change at some point where his slaves have to fight him to change him back. They win, he's back, more grinding and thats as far as I've gotten.

I probably missed a bunch of things as its been a while since I've read it but thats the basic jist of it. You can compare it to whats going on in the LN.