It might be possible for Illit or aespa to win the Song of the Year Grand Prize from Melon, and it will be less likely for Gidle or TWS to win it.
MelonYearly #1s since 2009, when the award was first awarded
2009 SNSD Gee
2010 MissA BGGG
2011 T-Ara Roly Poly
2012 Psy Gangnam Style
2013 Primary Johnny
2014 Soyou, JGG Some
2016 Twice Cheer Up
2017 (Ailee's OST is NOT eligible for Grand Prize since OSTs are not counted for Grand Prize)
IU Through the Night - #2
2018 Ikon Love Scenario
2019 (Anne Marie's 2002 not eligible since she is a foreigner, and #2 and #3 are from cheaters)
2020 Zico Any Song
2021 IU Celebrity
For 2017 and 2019, I consider Through the Night and Boy with Luv as the yearly #1s since the actual #1s are ineligible.
Here are what the #1 singer/song had won from Melon Grand Prizes
2009 - Song , Artist
2010 No award
2011 No award
2012 Song
2013 No award
2014 No award. Soyou, congratulating Taeyang who won the Song of the Year award, said "we will never make it. Not even after the world ends". More on that below.
2015 Song, Artist
2016 Song
2017 Album (actual #1 not eligible because the song was an OST)
2018 Song
2019 Song, Album, Artist (actual #1 not eligible because she is a foreigner)
2020 None, which might be why Zico decided to join Hybe
2021 Song, Artist
2022 Song. IVE finally won the first Grand Prize for Starship, avenging Soyou.
2023 Song, Artist
Even a renowned artist like Zico was not awarded a Grand Prize despite of claiming #1 in the yearly chart.
I think if aespa can keep its boom, it will win the Song of the Year award, or if Illit wins the SotY , probably the Artist award.
It might be who choose to show up on that day, but given its history, Gidle and TWS would not be the first choices.