(Please don’t ask naively how US controls mass-media, no desire to follow up on that.)
Not substitution, and you somehow missed the fact that it's China's CCP, not ByteDance. It's China's CCP that acts through a de-facto shell corporation called ByteDance, the same CCP that stands behind the Uighur genocide, Tibet annexation, threat of invasion of Taiwan, etc. That's who you are defending as the desirable option.
https://www.fcc.gov/proceedings-actions/mergers-transactions...
https://www.reuters.com/breakingviews/biden-admin-delays-enf...
https://www.theverge.com/2020/3/6/21168079/grindr-sold-chine...
Are you even aware of the context of the reasons why Tiktok went dark? Did they do it with no provocation? By accepting the US's arguments for the Tiktok ban we're just aligning ourselves with the same ideology of "the enemy" you're trying to malign.