Hi!Bye Mama has three generations the female leads mum and the female lead’s young daughter. FL’s mum know she’s come back.

Go back couple and Hello Me the mum’s don’t know.

Go back couple - it’s absolutely heart warming to watch the mother and daughter reunite in their past timeline.

There aren't so many Kdramas when it's the FL who is travelling back in time and usually she travels far in time in Joseon or Goryeo area, so no mother-daughter bonding.

I agree that there are very few shows.

In Familiar Wife the fl didn't know that the timeline had changed, but her relationship with her mother was so drastically different in the two timelines that it was heartbreaking to watch.

As other beanies have suggested, Go Back Couple is the drama he/she needs to watch.
Not being exactly the same theme, but maybe While you were sleeping is another option.

Most people will suggest Go Back Couple (rightfully so), so I would like to go with a more unorthodox choice - Splish Splash Love. It’s a 2015 drama special starring Kim Seul-gi (oh how I WISH those words were much more common) and Yoon Doo-joon, where a beleaguered high school student time-travels to back to the Joseon dynasty. There’s a ton of fun fish-out-of-water hijinks, genderbender shenanigans and a surprisingly heartfelt romance (as in, my heart is still feels the emotional devastation). However, the heart of the story is the strong mother-daughter relationship between our always-stressed protagonist and her mom. This one is so iconic and beloved for a reason.

Hello Me fits, I think. The mother interacts with both the younger and older versions of her daughter. And it's coincidentally one of my favorite dramas of all time.

God's Gift: 14 Days is not a big leap, time travel-wise, but it's enough for the protagonist to revisit her relationship with her mother (while all the other crazy stuff is going on).

It’s been recommended and will reco it more, Go Back Couple! xD