Recommendations

Both are about Korean letters.
One is historical the other one is during Japanese invasion
Both are very interesting. How Korean words form.

Both series focus on the undetermined nature of the female lead's relationship to the male lead. Suiyobi 22-ji dake no kare is the much more PG version of a undefined relationship, with arguably a time limit on the couple being 'together'. I also just really feel like both series have a similar vibe to them as well.

Both dramas uses double male leads and are of crime solving/ conspiracy genre. Though background are set in different era, overall story plot are similar

Both are crime solving natured dramas and a lot of plot twists and turns are buried in the stories! Equally enjoyable and some bromance too!

Both are of crime solving nature and had lots of plot twists and turns hidden within the stories. Similarly, both dramas leans closer towards double male leads but the female leads are equally important.

Though Tientsin Mystic is definitely a better made drama of the similar genre. Both dramas had the double male lead casting and both are also of the crime solving genre as the dramas look for what lays behind the conspiracy.

Both films star Liza Soberano and Enrique Gil. Both are romances that are a bit angsty. I think they give better performances in "Alone Together," particularly Liza's. Overall, both are recommended because their chemistry as a real-life couple is amazing.

Both star Liza Soberano and Enrique Gil. Worth watching for the couple's great chemistry, though "My Ex and Whys" has a slightly problematic storyline.

"Must Be Love" is Liza Soberano's film debut. Enrique Gil has a cameo in the film as a possible love interest to her. It's possible that this is when they first met and they began dating in real life a year later!

"Just the Way You Are" is Liza Soberano's and Enrique Gil's first film together as the main leads. It's a bit clique but it's still enjoyable. I think "Everyday I Love You" is the superior of the two though.

Same author
The same « love and intrigues » atmosphere
We also have two couples who kinda exchange their partners

Both stories feature a psychologist who needs to explain away and deal with the supernatural appearances of ghosts. Both works have plot twists that are pretty much identical.

Both females lead get into a car accident which bring her into a coma so her soul have a time limit to accomplish some missions to go back into her body otherwise she die.
All that with the help of a Reaper who forgot all is past life as a human but start to remember step by step...

Music influence this love story between FL & ML. Both of them studying in the same school & they both play musical instruments. FL got a secret but she couldn't tell anyone about it. Yamazaki Kento is famous playing high school student roles that adapted from manga/comic book.

Both dramas show the struggles of a start up company relating to food. Both dramas are from the perspective of the male lead. The drama contrast in that kkondae intern has a second older ml who is something of a father figure to the primary male lead.