I don't think Blackpink is popular enough in the US to get the superbowl spot. Their highest charting song on Billboard is a Selena Gomez feature that peaked at #13.
BTS is tricky because they had multiple songs that reached #1 but unsure if the general public cares for the songs much. Also, they had to take a long break due to mandatory military service, so those songs are 5 years old and unsure if they're still viewed positively. I think if their album that's releasing this year performs well, then there's a chance they'll get to perform at the superbowl. They have to make sure their songs on this upcoming album is a hit
Kpop demon hunter most likely doesn't get considered because their song is tied to a film and the sequel is like 3-5 years from now. Their only chance is if the group actually becomes a thing and if they replicate the success
Honestly, I don't really see it happening with a kpop group headlining the next superbowl. Plus, unsure if there's that much growth for the NFL in the Asia region. Plus, the superbowl would be airing at around 8am there, so they might not view it as worth it. I think they're most likely going to go with somebody like Bieber or a female musician.