In short, a president has substantial powers (granted by Congress via IEEPA and CFIUS) to institute a ban or force a divestment of any company "engaged in interstate commerce in the United States", if "national emergency" or "national security" is involved. So, legally, it seems that president can ban TikTok, under certain conditions (that may not be so difficult to achieve). The link above only explains the current legal framework, not whether banning the TikTok is in itself a good or a bad thing. IANAL, so I can't judge the competence of the presented arguments, but it is written by a respected law professor.
It would be interesting to know whether the big companies have addressed (at least partially) their GDPR compliance. Maybe they do just "play Russian roulette" like you said, and hope for the best.. Of course, implementation guidelines are not yet fully defined (like WP29 opinions, some of them will change, even then, those opinions are not legally binding).
I'm sorry, but your comment about Yugoslavia is extremely simplistic, if not outright wrong. While ethnic tensions certainly played a large role, the causes for the war were numerous, and also include outside influences (end of Cold War, geopolitical situation, etc.). BTW, Tito was dead for 11 years before the war started, and while he certainly was a dictator, albeit somewhat more lenient than other communist dictators, describing him as a "violent warlord" is a mischaracterization.
https://www.lawfareblog.com/tiktok-and-law-primer-case-you-n...
In short, a president has substantial powers (granted by Congress via IEEPA and CFIUS) to institute a ban or force a divestment of any company "engaged in interstate commerce in the United States", if "national emergency" or "national security" is involved. So, legally, it seems that president can ban TikTok, under certain conditions (that may not be so difficult to achieve). The link above only explains the current legal framework, not whether banning the TikTok is in itself a good or a bad thing. IANAL, so I can't judge the competence of the presented arguments, but it is written by a respected law professor.