First Immortal of the Sword - Chapter 1936: Chaos Source

In the year 3021 of the Western calendar, the last world war broke out and the earth was destroyed.
A group of survivors left their homes to settle on new planets. New races, new classes are born. Cities began to be built, countries rose one after another, conflicts between different races intensified, and social order was re-established…
The transformation from a survivor to an aggressor was but a moment.
This is a world where the strong are respected and the fittest survive.
Shang Ping was reborn from the earth in the 21st century to this planet. The moment he woke up, his fate had already begun to change.

Content Labels: Strong Soul Conversion Court Marquis Heaven’s Chosen
Search keywords: Protagonist: Shang Ping ┃ Supporting roles: Solan Edrich, Liu Xi, Austin ┃ Others: future time and space, battleship, interstellar war, rebirth, distant starry sky

- Description from novelbuddy

Betrayed and butchered by his treacherous best friend, Carlo's soul was consumed by an insatiable thirst for vengeance. Reincarnated into the body of Eduardo, a lowly servant, he vowed to dismantle the ruthless Mafia empire of Marcello Diabolo, the monster who orchestrated his brutal demise.But plans went awry upon meeting Marcello.“You're mine, Eduardo. Why don't you spread your legs for me”Eduardo's resolve wavered as Marcello's seductive pull intensified.“Run, and I'll catch you. You'll never escape my bed” Marcello warned.“I need you inside me, not once, not twice, do it until I break”Torn between revenge and desire, Eduardo's secret threatened to expose him. Would Marcello's obsession endure, or would Eduardo succumb to his enemy's passion?Will Eduardo's quest for vengeance consume him, or will Marcello's fiery passion reduce his resolve to ashes?

He died on the wedding of the girl he had a crush on, after a long and successful career. After convincing Yama to send him back to the world, he decides to fix the areas in which his life went wrong. Realizing the lack of love and romance in his past life, he sets out to conquer the hearts of various women.

One day, Zhang Fan, a poor medical student, receives a medical system from the future. This turns him into a new shining star in the medical field. Along the way, he must face medical corruption, competition, and infighting from other doctors, and even find time for a love life as he strives for the top of the medical field!

- Description from Novelupdates