To the Other World as a Side Character

What is it like to live a life without regrets? Shino Takasaki had a life full of regrets, yet he continued to move forward, entirely dead inside and just putting on a mask for others; nevertheless, after he was involved in an accident, he was given a second opportunity to live by god in another world. He sets out on his rebirth, believing it will be like his favorite Isekai manga, only to discover he will be a secondary character. What awaits us? Will he be able to live a life free of regret?