Transmigrating to the Carefree 1970s

Upgradeable pocket dimension + spirit spring + immense strength

A story about a girl who transmigrates to 1977 and becomes an abandoned daughter. After getting revenge on the scoundrels, she returns to the city with an older man, marries him, and they enjoy a sweet, leisurely life together.

Content warning: After taking her revenge, the heroine becomes extremely laid-back. This is entirely fictional and set in a completely imaginary world.