part D. "The record before us adequately supports the conclusion that Congress would have passed the challenged provisions based on the data collection justification alone"

This is belied by the lack of laws (and lack of provisions in this law) preventing American companies from collecting data and selling to the highest bidder, including China.

from the opinion: "[Tiktok] further argue that the Act is underinclusive as to the Government’s data protection concern, raising doubts as to whether the Government is actually pursuing that interest"

ie what you're saying...the Court replies:

"the Government need not address all aspects of a problem in one fell swoop...Furthermore, as we have already concluded, the Government had good reason to single out TikTok for special treatment"

Congress can solve one problem without needing to solve all problems.