New Asian Artist that went to JO1. On Billboard Japan JO1 was ranked #18 for the overall group rankings.
At the same time NiziU was ranked #15, Snow Man was ranked #12, Six Tones were ranked #11 and Yoasobi was ranked #8. All of these artists debuted in 2020 or in Yoasobi's case December 2019. I can see them being ahead of NiziU as technically when the award was given NiziU had not debuted yet but the other groups no way.
On Singles sales, JO1 was ranked #14, 16, while Snow Man was ranked #3,4,5. Sixtones was ranked #3, #5, #6 (#3, #5 were colabs). JO1 had 2 Platinum's but Sixtones, & Snowman had million sellers.
In downloads Albums NiziU was #2 and JO1 wasn't in the top 100 at all.
In download songs Yoasobi was #7, ,#28, 57, #68, #69, NiziU was #17. JO1 wasn't in the top 100
In Streams Yoasobi was #1,23,62,67 and 76. NiziU was ranked #11, JO1 wasn't in the top 100.
By any metric the award should not have been given to JO1 but someone else as there are 4 groups that ranked higher then them.