There is a subset of fantasy literature called "Alternate History". I won't go long explaining what it is; "Man in High Castle", by Philip Dick, is one of such works which might be familiar. It is about how history would have progressed if it went differently.
Park Bogum, himself a decent singer, inadvertently did change KPop's course when his Love in Moonlight, basically his one-person show, sank Scarlet Heart : Moon Lovers, starring Lee Jieun and many others.
If the reverse had occurred IU would have largely retired from singing, like Suzy, and would have moved on to become a full time actress. She might release a single once in a blue moon, but would largely be recognized as an actress who was formerly a singer.
Here are who would have won the awards where she had won back in 2017, 2018 , 2021 and 2022
2017
Melon Awards -Digital - Akmu
2018
Golden Disk - Digital - Twice's knock knock. (They don't give awards to people like Akmu. )
2021
Now it becomes quite interesting.
The very reason IU won the Grand Prize on Digitals with Blueming, released on Nov 2019 , when from the same award she had been disqualified with Good Day (released Dec 2010) and You and I (released Nov 2019), was bending the rules and it was to prevent a clean sweep of all awards by BTS.
Since the intention was to disallow a sweep all awards by BTS, most likely the winner would have been Zico, who was in the military at that time, or Red Velvet, who was #10 in the melon yearly ranking on 2020 (#8 after removing Eight and Blueming) but was the highest idol group after BTS.
So Golden Disk Digital - Red Velvet's Psycho.
2021 Melon
Digital - Aespa
Album of the year - since BTS and Aespa were not available on the award day, I would say that Lim Youngwoong , who was there, might have won as a surprise choice since someone had to be present on that award ceremony.
2022 Golden Disk
Digital Grand Prize of the year - aespa's Next Level.
Aespa was given 'Artist of the year' award, not considered as a grand prize in Golden Disk, as a runner up prize so if Park Bogum had been defeated by IU back in 2016, aespa would have won a Grand Prize in 2022.