The Love Lasts Two Minds (2020)

Nothing similar about story though but FL is same
And I like both the dramas...

The female leads from both dramas lose their memories.
Both are costume/historical setting dramas/not modern setting.

Both have a very meaningful message towards humanity and well structured plots. The two come with detective activities and have surprising hidden villains.
But TLLTM has a much better ending, though at first its pace is not as suspenseful and fast as Luoyang. It also focuses more on the romance side compared to Luoyang.

Both FLs lose their memories and start entirely new lives, while the MLs who loved them re-enter their lives and help them.

Both FLs grow up as sweethearts with a man who to protect them wipes their memories and sends them to marry another man, continuing to support them from the background. In PS the FL ultimately falls in love with someone else, in TLLTM she returns to him. Both dramas have palace scheming.

Not that similar dramas but I feel like if you enjoyed Yu Meng Long's "emotionless" kind of acting, you'll like both of these dramas.
Few more similarities:
- ML played by the same actor
- calm ML who holds a higher status and is physically weak (a bit downplayed in The Love Lasts Two Minds)
- FL knows martial arts