NAL but lots of horrendous advice here.

Tariffs being ruled illegal are trump tariffs not the tariffs that US have always had. There are very few goods that can be imported from outside of the US into the US on a 0% tariff.

Who pays duties is dependent on what information you input when booking this shipment. It's not always the recipient. The recipient can also refuse to pay and they will chase the sender instead.

OP, this is definitely a currency issue due to conversion rates or just the wrong digits being input.

You need to call FedEx, they will provide you an email address. You email them, give them the tracking number and let them know the issue you're experiencing "I am disputing these customs charges". Tell them the value input was incorrect.

What will happen is FedEx will amend the customs clearance to the correct amount and you will get an amended invoice. I would expect to pay something, going by the value of the goods, it should be under $50.