Rearrange

Botkawi has forever been in love with Praemai. His life is forever changed when a musical crystal ball he bought as an important gift for Praemai transports him back in time to the age of eighteen. Everything turns upside-down. Instead of fulfilling his hopes and setting things right with Praemai, Botkawi somehow ends up in the arms of Pisaeng. Thus begin their cat-and-mouse games with Pisaeng chasing after Botkawi. Old feelings for Praemai, however, become a detriment to their blossoming romance. Enraged, Botkawi keeps twisting the crystal ball in an attempt to get his desired results.

Youthfull romance with music as the underlying premise.
Set in high school life of the characters
Second chances to the main characters

Both have plotline that is based on going back in time through death to get your life in order. "Restart" is more sensual, handles mature topics and has a crime plot, while "Rearrange" is softer, leans more on the youth aspect and towards saving somone, rather than getting revenge.
Both are good in their own way and for different watch experiences

They have the bubbly, summer, fluff feeling in common qnd both are about teenagers in school, that have a boyband that they want to win a special contest with. MSP has more ckmedy, while Rearrange tackles more interpersonal relationship related topics.
What I just noticed is that they both, in their own ways, handle homophobia, academic pressure, loss of a loved one, rejection and different friendship dynamics.

Both are BL dramas that has time travel, with the main character as a depressed/jaded working adult returning back to high school in order to fix things/fix his past. Rearrange is a Thai BL while Love for Love's Sake is a Korean BL.

In both dramas, the plot follows the main character many years later returning to the past and trying to change the fate of their first love who has died.

Made by the same company. Both are in High School. Shades is a GL and Rearange has a side couple that is GL, Mint and Opal are a couple in both series. Flute who is the mc in Rearange is the director for Shades.