MTL - Dressed As a Body Double Slag a and His Aunt - Chapter 79

This is probably the story of a modern man who became the Seventh son of Kangxi in the Qing Dynasty. This is probably the story of how the Seventh brother Yinyou worked hard and fell in love by the way. So there is no doubt that this article is ambiguous, and it is easy to guess who the couple is.

- Description from Novelupdates

A supreme expert in the Immortal World had died, and a strand of his soul returned to its original body on Earth. Tang Xiu discovered with amazement that ten thousand years passed in the Immortal World, yet only a single year passed on Earth.

Ruthlessly betrayed by his lover and trusted friends, Tang Xiu found that his soul went back to his previous body on Earth, and, despite he spent 10,000 years in the Immortal World, just a year has passed on Earth and many things have changed. Having an unsurpassed knowledge, Tang Xiu will protect his loved ones and go back to the Immortal World to take his revenge.

- Description from Novelupdates

Xia Yuqing is a shut-in+fujoshi from the 21st century. After an accident, she transmigrates into the body of a young princess forced into a political marriage to another country.