Definitely https://www.novelupdates.com/series/superstars-of-tomorrow/ Well-known Composer Fang Zhao was in the glorious stage of his career, when the Apocalypse arrived; After finally experiencing the bitter difficulties of a thousand dangers, when the Apocalypse was simmering down to an end, he collapsed; When he opened his eyes, he was reborn in a New World, 500 years after the end of the apocalypse, in the body of a student who had been dumped barely after graduation, who had been cheated of his hardwork barely after he started working… The World of the Future, Virtual Idols PK Real Idols “Every time background music plays in my head, I feel like there is nothing to be afraid of.” —Fang Zhao Toward the end of the apocalyptic period, Fang Zhao lost his life. However, instead of dying, he found himself 500 years later in the body of a young and aspiring composer who shared the same name. Having received a second chance at life, Fang Zhao sets out to achieve the previous owner’s dreams. Armed with the experience of living through an apocalyptic age and his profession as a composer before that period, Fang Zhao uses his talent, wits, and knowledge to make his mark in the entertainment industry of the future.
I second Superstars of Tomorrow. The MC is literally a grandpa in a young body. No indecent thoughts whatsoever. The King's Avatar. I wonder how people actually forgot about it. Unique Legend. Undervalued novel but one of my favorites. Pro tip: The moment you start imagining MC in the first chapter with slouched shoulders, trembling, cowering, and overall everything a pushover MC is - STOP IMEDIATELLY. The key to getting the best out of this novel is the MC. No slouched shoulders, no cowering, adjust everything down to facial expressions, and you get a deep character - 'depth' is in fact the best word I can use here, since due to the method, the character could appear differently in someone's else mind. It doesn't get in the way of reading. In fact, it's aligning perfectly - I had, throughout 12 volumes of reading, maybe two instances where written desctiption differed from the image in my head. And that's all. The reason why this method works is actually thanks to the way the novel is written. The novel has "blanks" that allow the method to work. Without a lenghty explaination I can't describe it much better. I'm talking about it because this novel is such a gem in my head - and I either see two types of readers; those that didn't like the MC, even dropping the novel, and those that liked it regardless, or liked the MC too. So if you read it and you enjoy it regardless of, that's fine, but if you read it and you don't, maybe give it a second chance.