Both revolve around polygamy
Hare-kon is less dramatic and more comedy, but Raise the red lantern is thorough and goes in-depth to show polygamy

Both dramas focus on Contract marriage without any previous knowledge of the other party, yet for personal reasons to fulfill the expectations.
The leads fall in love during the contract.

Contract relationship is the main focus in both dramas.
The leads are not so fond of marriage, thus they enter contractual relationships for personal reasons.

Both dramas revolve around contract relationships between the leads, which during the process one of them falls in love with the other. The stories are a little different, yet the main focus is the contract between them

Contract marriages for personal reasons. The leads fall in love during the contract.
The vibes are a bit different, but both are mainly focused on the contractual relationship

The stories are somewhat different, yet they have contract relationships in which the leads fall in love with each other.

Both are really romantic dramas
Both have body swaps
Go princess go has time travel too, but the day of becoming you doesn't

The FL in both dramas is Liang Jie
Both dramas have body swaps ( one between the ML and FL, the other one FL with the real body owner)
Both are really romantic and have great chemistry

Please come back Mister has body possession by two old ajussis who are reincarnated. They act weird and it's really fun to see them, yet The day of becoming You has no reincarnation but they swap bodies.

The only similarity between these two is the body swap
The stories are totally different and have different genres

Both dramas have Body Swap
The stories somewhat turn out to be funny for both leads
Big depicts the teenage side of being a different person, But the day of becoming you both are adults

The stories both revolve around fighting for justice
There is Amnesia in Both
similarly, the background stories are really elaborate and keep you entertained