They often seek to create calamity and crisis - with Covid; spreading fear (of immigrants, etc.), hatred and violence; disrupting health, education, and housing; international peace and security (NATO, Ukraine, etc.). You never see them spreading calm and peace - crisis seems necessary to their movement.
Tanking the economy does the same thing, but it is a much bigger step that impacts many of their supporters. What is their exit plan?
I expect part of their plan is to blame others: They will blame Democrats somehow, and other political enemies - it doesn't need any basis because the Dems don't have any effective means of refuting it to the public; whatever the GOP says becomes reality. I suspect they'll use it to ramp up hatred and fear, blaming their current objects of hatred such as immigrants, minorities, certain religions (a traditional object of blame, the right has already been normalizing antisemitism and general prejudice - which makes antisemitism inevitable. Rogan recently hosted a conspiracy theorist blaming Jewish people for 9/11, for example - how long before does he blames them for the economy, 'undermining President Trump'), liberals, etc.
Edit: I did some rewording
And yeah I think your read on how they'll manage the fallout of this is correct.
As for Trump himself, I think he truly believes the rest of the world is taking advantage of the US and tariffs are a way of setting things right. My guess is that in his view, the country (or at the least the rich people he cares about) will benefit from all this.
I don't think he has any such belief, and would abandon those 'beliefs' in an instant if it suited the only thing he cares about, himself.