But it's a Chinese SoC company. I'm wondering if the fight between US and China will widen to any SoC companies in the long term.
Probably not, you can only escalate this trade war so many times before it becomes unsustainable by one or both parties.
China will probably retaliate by banning a major US tech company, maybe Apple? Keep doing this a couple of times and pressure/lobbying/economic damage will force a resolution.
If China bans iPhones I'm 100% positive they'll just be smuggled in.
Sure, but I am also 100% positive it will hurt Apple revenue a LOT.