Oathbreaker: A Dark Fantasy Web Serial - 1.4: Memory of a Dream’s End

Lin Xiao was an orphan who strived to get stronger while living with his sickly younger brother in an unnamed small village.

She died in her prime as the Queen of Song.

After being reincarnated, she becomes a simple trainee.

Losing her former glory? It doesn’t matter—no one can compete with her voice as a beautiful singer.

Mocked by her lowly birth? It doesn’t matter—her true identity is enough to make the whole world tremble.

She owes huge debts? It doesn’t matter…

A powerful boss once whispered to her, “Your debt will disappear if you become my woman.”

But the proud her would reply, “I’m sorry. I would sell my art, but not myself.”

- Description from Novelupdates

It was only after Su Yayan's death that she realized that she was a malicious cannon fodder female character who became a scapegoat in a Mary Sue story.

An unnamed 34-year-old Japanese NEET is evicted from his home following his parents' death.

Upon some self-introspection, he concludes that his life was ultimately pointless.

Walking down a street he intercepts a speeding truck heading towards a group of teenagers, in an attempt to do something meaningful for once in his life he manages to pull one of them out of harm's way before getting himself in the way of the truck and dying.

Awakening in a baby's body, he realizes he has been reincarnated in a world of sword and sorcery.

He resolves to become successful in his new life, discarding his past identity for his new life as Rudeus Greyrat.