It would depend on the reason for the sanctions...

If the sanctions are to prevent buying the products of slavery, that's a moral issue, and violating the sactions is also a moral issue.

Same deal if the sanctions are to prevent selling things that will be used to carry out genocide/etc. That's a moral issue, so violating the sanctions is a moral issue.

I don't think there's an alegation that the GPUs will be used for immoral purposes, just that the US government has national security concerns. Those concerns may or may not be valid, and may or may not be served by having trade sanctions applied effectively, but I don't think that's a question of morality.

It's not de facto immoral to violate the law. It could be immoral to violate the law and conceal it.