Basically mc and ml will keep entering these cycles, and it will keep repeating, author just feeds us scraps of lore along the way. So as far as I'm aware; Mc died young from cancer and joined up with a system. Ml, who's the God of the system, fell in love with mc and keeps interjecting himself into to role of the love interest. During the immortal arc (which was an arc inside an arc), where the mc best friend was killed the mc was heartbroken and the ml resetted the mc's memory (from the clues given, it's not the first time he's done it). The two have been going through the motions since. And the most recent arc just has a peanut gallery in the form of the white lotus classroom (which is one of the titles of this manhua)
i thought i understood but after the ml kills mc's friend and makes the mc forget, i lost the plot again ╮(￣▽￣)╭ it kinda feels like the story "restarted" in some way but anyways, the last 2 worlds have been spicier (for a manhua) and i'm not complaining