Le sserafim and newjeans are from the same company and both are doing well. They are proof that it's doable to have 2 top groups at the same time, they just needed to be manage properly
Technically, LSF and NJ come from two different companies. They have different management, different production, and different CEOs. They don't really share anything except for the building, its facilities, and the Hybe's hype. In short, Lsf and Nj debuted with a whole company dedicated just for them instead of sharing it with other groups. While SM has its own division, all their groups still under the same management and sharing a lot of things. It will be much harder for them.