I don't think steelmanning an argument works if the argument is made in bad faith. Steelmanning should be about trying to understand legitimate reasons for a positions, not bullshit arguments. About being fair and intellectually honest, and not about trying to act like a PR firm for the other person.

That said, if you want to make sense of the reasons behind the tariffs, I can offer a couple that would be reasons why Trump would implement tariffs.

1. While they are within his power, they are a cudgel he can use to hurt his enemies and show favoritism (and be open to bribes to get them lifted).

2. Trump has a weird obsession with tariffs, even after he lost a trade war with China in 2018 and had to bail out farmers with a bailout larger than the one to General Motors.

3. Also, as one of Trump's Wharton business school professors has stated numerous times, "Donald Trump was the dumbest goddam student I ever had."