Can someone explain Day6 dominating South Korea Charts phenomenon

Been checking out recently that Day6 is dominating South Korea Charts with multiple songs, it's the first time I get to know about them and their songs are so good, especially their new hit Melt Down. The last time I think seen a bunch of songs from an artist dominating South Korea Charts was new jeans (last year) and twice (6-7 years ago).

With this phenomenon, can someone explain how did they explode now and how did they climb to the top? It's super hard and rare especially it's their 9th year now, they even have old songs climbing to top10 melon, how impressive is that!