A.C.E dancing the Arirang (Traditional Korean dance)

Arirang isn't a traditional dance, it's a traditional song (or rather, it's kind of a loose set of traditional lyrics that many artists interpret in different ways). No criticism to the OP, just explaining for people who might not be familiar with Arirang. You can perform traditional dance to Arirang, but the title and the concept belong to the song, not the dance. Each region of Korea has its own version, with many variations on the theme.

The A.C.E. version is a pretty unconventional version of the song, themed around the "Jindo Arirang" from South Joella province. For some context, the UNESCO explanation when they declared it a cultural artifact:

And an explanation of Jindo Arirang specifically, This one also shows traditional Jindo dance, which is where a lot of the choreo comes from:

Here's a different version of Arirang, which deserves to be seen just because it's stunning and So Hyang GOES OFF. The melody she uses starting at 2:55 is closest to the most common version of the Arirang now. This made me tear up, honestly, it's that well-sung:

And a more traditional version of the same variation used above, to get an idea of the melody Korea nationally uses now as a theme at events like the World Cup or Olympics. This can probably be considered the most common Arirang now (though regions still learn their own versions as well). It was performed at the annual "Arirang Festival" by Song So Hee:

Basically, none of these groups are doing the song "wrong" (because the whole concept isn't confined to a single melody or even lyric line), and the A.C.E. interpretation is interesting because it's more geographically local than you would usually think to hear in major productions of the song. I do like how they're innovating, because again, you can't really get this wrong as long as it sounds good, and the choreo was lovely.