Chapter 4: becoming friends with the twin singers and adventurers. then conquer dungeon A-class
Chapter 5: class S dungeons appear in the world, and many class S people appear (definitely reference to Solo Leveling).
Chapter 6: MC fights gouki, and as usual, MC wins and uses his spirit power to deceive the people around him. at the end page, we see rei wanting to spar with MC

dunno man, this is looks like 2nd solo leveling for me (diffrent only in story MC got back from isekai)
thank you for translating & upload 3 chapters