Something with ~0% market share outside of China and which trades the US having root for China having root is not a viable alternative.
In theory you could have something produced by a country other countries might be willing to trust, but the number of countries that are both trustworthy and large enough to sustain a globally-viable platform is practically the empty set at this point.
Which means the thing it calls for is something open source, since that both allows contributions from multiple countries and solves the trust issue by leaving no single entity in control of it.
Viability is debatable. There are tens of millions of smartphone users in the US who are vastly more exposed to US law-enforcement abuses and intrusiveness than anything China would care to try. Chinese emigres excepted.
In other words China doesn't have to be trustworthy as long as the mountains are high and the emperor is far away.
One of the ironies of the TikTok-China discussion was that as an individual in the US, I would much prefer the Chinese govt have access to all my data over the U.S. government, just like I suspect individuals in China would be much better off if the U.S. government had all their data over the Chinese government.
So giving your data to the Chinese government, while not a great solution, may still be preferable over giving it to the U.S. for someone in the EU given the closer relationship between EU governments and the U.S. than EU governments and the Chinese government.
Of course, this may be the opposite of what you want from a national perspective.