What is a mid-tier group?

For GG, I think Lovelyz is the perfect mid-tier. Their sells are respectable, but not 100K respectable. Digital is quite meh. They don't have many show wins. They have an almost hit, but no real no question asked hit yet. They aren't total nugus as some members are active in varieties occasionally, but not quite the one member getting all the fame and sustaining the group syndrome too. Their brand reputation is middling as well. Their company is also the perfect definition of mid-tier too.

Somewhere in the middle but not close to the top. Lovelyz and Day6 are some examples.

For BGs

Top Tier (1M sales+)= BTS, Seventeen, EXO, NCT

Mid Tier (200-800k)= TXT, Stray Kidz, Ateez, The Boyz, Suju, Shinee, Enhypen, Treasure, Astro, Nuest, MonstaX

Bottom Tier (under 200k) = Golden Child, Cravity, Drippin