Debut
Dalla Dalla and Bon Bon Chocolat: Both gained a lot of attention.
1st comeback
Icy and Adios: Both gained a lot more fans. Everglow got more popular. Icy got 12 wins.
2nd comeback
Wannabe and Dun Dun: Gained a lot of fans again. Both their most viewed music videos.
3rd comeback
Not Shy and Ladida: Lost some fans. Comebacks not received well.
4th comeback
Mafia in the morning and First: Again, not received too well. A lot of people were disappointed.
5th comeback
Loco and Pirate: More people disappointed. Lost some more fans.
Also, I'd like to point out how their releases are a month apart.
Dalla Dalla: February 2019
Bon Bon Chocolat: March 2019
Icy: July 2019
Adios: August 2019
Dun dun: February 2020
Wannabe: March 2020
Not Shy: August 2020
Ladida: September 2020
Mafia in the morning: April 2021
First: May 2021
The only time it didn't happen was with Loco and Pirate
Loco: September 2021
Pirate: December 2021