Here's the start of an idea:
Those of us who end up directly getting a tariff payment demand on a purchase from overseas (especially if the purchase is from Brazil) might want to consider filing a personal Federal civil action against FFOTUS, as a private person, for recovery.
The basis would be an ultra vires government action, not authorized by law (this is why the Brazil path is particularly interesting, because there is no real way that this is in any way authorized by Congress.)
Now, there would be lots of procedural hurdles - lots of assertions that the acts are governmental and this subject to things like sovereign immunity constraints (and statutes requiring various pre-filing steps, such as demands via certain channels.) But those may be less effective now, particularly after SCOTUS grant of imperial immunity - and thus declaration of non-immunity - for various kinds of actions by a person who happens to hold the office of el-presidente.