I thinks album sales wise they will continue to grow noticeably.
But legacy and fame, I personally believe the next step that hinges on the success of this comeback is Musical Respect, if that makes sense!
Like they're getting more recognition for the quality of their music, but in the west there's still a distance from the art when they're discussed, like both the media and other famous people are still kinda baffled and mention their fans and lots of surprise why they're so popular? So if this album is received well critically, and they do well on SNL/have a great performance there and the BBMAs, that could lead to a nom at the Grammys and have more of a Beatles path, from not just remembered as that Korean group that got super popular worldwide but instead like an artistic legend'. They transitioned from dudes known more for the screaming girl fan frenzy to one of the Ults, and now no one remembers that Beatles fans were mocked for being crazy girls obsessed with girlie-boys with long hair at first.
I'm really nervous, actually; this is a critical point, and everyone is waiting for them to stumble in some way even those out of their control. They'll be more than okay if this is their (in the clouds, almost in space) peak and millions of fans will be with them until a day they disband for good, but I think they want to take this as far as they can, and I want that for them too