I think he needs to start subsidising American industry instead. He can do both at once but if the government are not actively investing in industry and other methods to mitigate with the tariffs (especially with the money raised) it's a foolish endeavour.

I saw people on Tiktok and other social media saying AI chatbots (chatgpt) was the actual thing that came up with the reciprocal tariff formula.

Also, the UK doesn't have a trade deficit with the US. That's likely also true for the Taliban that got a 10% tariff, the formula just probably added a floor so no one (but Russia of course) scored zero.