Oh, it's hard work, but you can totally have trade deals and subsidize industries - you "just need to" get your trade partners to agree - Canada still has its dairy management system more or less intact for example.
Like ya, it'd be a lot of work (probably take years!) to get these deals going, but let's not lie to ourselves about what these subsidies are about - they're about trying to setup a more or less sustainable system in important industries that is supposed to last for decades. After years of "paperwork" it'll take years (maybe over a decade!) to actually come up to steam in production.
At least for the USMCA and EU, I think a lot of American interests are more or less aligned with partner interests. The obvious common ground is "let's work out ways to reduce our reliance in certain strategic areas from sources concentrated in China's sphere of influence". I think there's sufficient political AND popular backing of that that something could probably be figured out. Notably this might require that America itself "settle" for bringing back "western manufacturing" not "American manufacturing". That might be the hardest sell in this whole deal.
