Yes, Congress could pass laws banning tourism by foreign nationals if they wished. The constitution is explicit that they can do literally anything they want to regulate trade with other countries, and they absolute do regularly ban and sanction foreign bad actors. It has nothing to do with laws that exist. There are numerous such sanctions already in place against China and Chinese actors, and it's an inherent right of being a sovereign nation.
You have absolutely no rights to interact or do business with foreign actors. It cannot possibly violate your rights to be prohibited from interacting with China. Every single country on the planet breaks treaties when things change to the extent doing so is required, which is irrelevant, because China routinely bans US companies for the sole purpose of protecting their own state controlled entities.
There is nothing for the Supreme Court to rule on. There is nothing remotely ambiguous here and nothing that in any way resembles a new precedent. This is entirely standard behavior.