Me, I don't think it should be approached as a 1st Amendment issue but more like a 5th Amendment violation.
If I want to run TikTok on my computer or my phone or whatever, it's my property, and it's a violation of my property for the feds to prevent me from using that property in the way I see fit.
I really think we have let 5th Amendment protections go way too dormant in this country.