Star Instructor, Master Baek - Chapter 274: Awkward...

A man was transported to Ancient China and eventually became a servant of a declining household without a male heir. He utilized his wits and modern knowledge to help the household and eventually become trapped in the sea of political turmoils of the period.

- Description from Novelupdates

A scientific genius named Thomas Harrier was transmigrated to an imperial prince body after a car accident that took his life. He found out that he is in a world similar to our own with a timeline akin to early twentieth century. The body that he is occupying was the imperial prince of a failing empire who suddenly rose to power after a successful assassination attempt of his father. Unaware that the attack is just the beginning of what is to come. He faces many challenges throughout. Will Thomas Harrier be able to live his second life in peace while running an empire and getting it back to its former glory? Or will he succumb into a conspiracy lurking within the country's borders?

Expect some:

Cold war era techs.

Super battleship with advanced electronics, propulsion, and fire control systems?
Helicopters?
Missiles?
Modern medicines and equipment?
AC-130?
A nuke?
Challenger or Abrams or Leopard?
F-4 Phantom or MIG-21?
Colored TV's.

Everything!!!

PS. Cover not mine, I just found it on google.

Lin Yuan, carrying the “Door to Myriad Worlds,” transmigrated into the Great Universe of the Starry Sea.Here, the mightiest could obliterate star systems with the flick of a finger, and traverse millions of light-years in an instant.As a bottom-dweller, Lin Yuan could only rely on the “Door to Myriad Worlds” and his innate talent, “Against-Heaven’s Understanding,” to travel through countless worlds, silently growing stronger.【Your Against-Heaven’s Understanding allows you to cultivate the Muscle-Tenden Transformation Bible, comprehending the ‘Muscle-Tendon Transformation Blood Tempering Divine Technique’】【Your understanding is Heaven-Against, upon extending your comprehension to the Thunder in the Palm, results in the mastery of the ‘Thunder Creation Opening Technique’】【Your understanding is Heaven-Against, while observing the birth and death of worlds, leads to the insight of the ‘World in the Palm’】【Your understanding is Heaven-Against,, through studying the art of external incarnations, culminates in the ‘Self-Transformation Great Technique’】……In his unending travels, Lin Yuan ceaselessly grew stronger, until… he was unrivaled across all worlds.

Coco Coison, after her untimely death at the hands of a fairy, finds herself transmigrated into the body of Coco Hughes, a woman with a troubled past. However, Coco was bestowed upon an ability: she was given abilities similar to Lala, a garden fairy, as compensation from Lala's sister.Eager to embrace her new life and start afresh in this unfamiliar world, Coco soon discovers that her new reality is far from what she wanted it to be.She encounters the four husbands of Coco Hughes, only to learn that they harbor deep resentment towards her due to Coco Hughes's abusive behavior— both physically and emotionally.Despite her intentions to lead a better life, Coco realizes that she must go through the complicated relationships and work to mend the damage caused by Coco Hughes to the husbands, who are now tied to her fate.Coco Coison must confront her past actions in a world where she is both an outsider in the lives of those Coco Hughes has wronged while carving a path for her to separate herself from her husbands.However, they seem to have another plan.“Where are you going? Stay for the night.” The first husband who doesn't like her presence around the house had started to let her stay.“Coco, what the f*ck are you doing? I told you to not lift a hand after coming back from outside!” The second husband who likes slaving her, cusses her out from trying to make herself a cup of tea.“The librarian told me that you went to the main city to get me books again. I thought I told you to stop doing that and put yourself at risk?” The third husband who loves books more than anything else had scolded her for doing her supposedly weekly errand told by him.“Who told you to go and ask those mediators to sing for you? I'm here, I can do it for you.” The fourth husband who doesn't like to sing for her had made it his daily task to sing for her before she goes to sleep.Coco Coison only wanted to live her life peacefully and earn money so she could divorce the four husbands, but it seems like they didn't want that.“It seems that tons of leeches want to have you around, huh? How about we get ourselves busy and have some kids fill the empty space of this house?”