Industrial tariff disparities and the related overuse of WTO special and differential treatment by countries that have long since industrialized constitute a serious issue. But see these recommended reads for why the Administration’s blunderbuss approach is unconstitutional by any reasonable reading of the statutes he is considering invoking and administratively unworkable based on any realistic understanding of how tariffs are administered by the responsible US agencies.
Unconstitutional (Congress has not previously delegated this kind of authority to the Executive Branch, so if the President wants to act in this manner he needs to seek Congressional approval of legislation authorizing it):
https://www.lawfaremedia.org/article/the-case-against-ieepa-tariffs
And administratively unworkable:
https://www.cfr.org/article/donald-trump-wants-reciprocity-trade-heres-closer-look