Become famous another day

Description

Time travel to a has-been idol who debuted at the age of fifteen, and is still a high school senior.
The unscrupulous agent forced him to quit the industry. Without a job, there would be no income.
The top priority after time travel turned out to be to support oneself first.
But without a system or a golden finger, how could he replicate the miracle with only his own memory?
It's okay, after all, he is someone who passed the 985 exam on his own merit.
A new era, a new world, and struggle start with outdated idols.