Both are new. Storyline is light, I would say mediocre. Same pace, character's development.
Not for bindge watching, I prefer to watch such type after deep dramas.

Color palette, mood, maturness.
Tomorrow more dynamical, with more complicated plot, but in a some way they are similar

They are similar not in a plot or characters, but rather same mood, slow pace and not quick development of relationships

Both drama have similar plot, slow pace. Where stars land have more famous cast and a lot of heros, but the main line of leads almost the same, as their steps forward to each others. Tell me generally more calm.

It's unusual to give such recommendation, but still. They are not similar in terms of plot or charachters, but the vibe of the humor are the same. Sometimes very funny, sometimes bit weird, but still worth watching.

I looked through recommendations and cant agree with many of them.
I think not only period drama and time travelling ones should be recommend, but show with similar mood.
So, close to this drama is the Rooftop Prince.
Both are funny, still different. Both have time travel, including mix period and modern.
I would say that humor in My Only Song is close to Waikiki, but the Rooftop Prince is just regular drama with regular plot and with lot of funny moments. In My Only Love Song plot is not the base of drama, the humor style is the base.

I admit, they both show may be different in a way, but Hello monster is a first one, which I think about after watching Alice.
- both has a story with murders and the one who trying to find the trues;
- there are people with disorders, who choses different ways;
- mystery connected with relatives.
Alice is a modern one, Hello monster doesn't have science fiction part.