You can’t sue the federal government unless they give you explicit permission to. They have sovereign immunity except when they intentionally waive that immunity, such as with the Federal Tort Claims Act. You can challenge the constitutionality of a law or policy, fight to have it overturned, but you cannot seek repayment for damages caused by that law or policy without meeting the conditions under which the government has said you can.

The FTCA is the primary mechanism to sue the fed and the allowances of it are pretty narrow. Tariffs, even illegal ones, would likely fall under the discretionary function exception, which would mean that you couldn’t sue. But even if it didn’t fall under that exception, in order to sue, you must first submit an FTCA claim for repayment of damages to the goverment and wait for their response. Claims must be made within 2 years of the damages and they have 6 months to respond. Only once actually denied can you actually sue, and it must be within 6 months of their response. And then you have to materially prove damages directly caused by the federal government, specifically.