Both groups I feel could have been bigger than they already were if it weren't for their lazy companies.
Before BTS got lucky it could be argued EXO was the biggest boy group in kpop history. Their peak was insane at the time. They were slaughtering kpop with sales and awards and even performed at the Olympics.
Blackpink came in with hype from their older sister group 2NE1 and with Teddy at his peak after mastering his craft with BigBang and was able to achieve global success more specifically the US which helped them become the second biggest girl group of all time after SNSD.
BP success seems to be lasting longer but that's only because YG releases a new group every 5 years. Meanwhile SM releases a new group every two years so a lot of fans move on to the newer group. With all this in mind who do you think is #2 of 3rd gen overall?