Some of these bans are a matter of political operatives stoking vague fears for personal or ideological gain. That was almost certainly the story about the TikTok ban. And some of it is actual intel that will get declassified in 50 years. That may be the story behind Huawei.

Given that this administration likes to use the threat of bans and tariffs pretty liberally, it's probably the former, but look at it this way: the US govt is known to have shipped backdoored networked hardware to overseas customers they wanted to snoop on. In China, the govt is more authoritarian and more integrated in the industrial supply chain; I'm sure they do that shit too, because why wouldn't they.