ifans talking about what songs are sajaegi when we don't even live in Korea to see how succesful are the songs in the real world might be one of the dumbest things ifans do. It's really unlikely any of the songs mentioned are sajaegi, it's possible they've been promoted a lot or that they became viral, but I'd ask people to be a bit respectful and don't make those claims when there's literally no proof of anything.
It's really unlikely How sweet will surpass Supernova, at this rate it should take 4-5 weeks and in that much time other songs would probably show up. Only way I can think is it being boosted by the single later this week, but I still have many doubts about the performance in Korea, it looks like they're going to be promoting a lot in Japan.
It looks like Spot is not gonna have too good longevity, also I doubt Armageddon will rise more. Supernova on the other hand should definitely sweep the sotys based on digitals despite being released in May, it's the biggest song of the year without any doubt, I hope the judges will be fair and make up for the bad timing in the end year awards.