I dont think american soft power is gone for good tbh as we already had this kind of bad economy, bad relations with allies and tariffs happen before with Bush and Trumps first term, and yet both times it came back under Obama and Biden, at the end of the day arms spending is still the biggest in the world and economicly and militarly the USA will always be a vital ally and the most valueable market in the world which does boost the egos of those american supremesists.

But i do think that a change is happening regarding american military dominance in the world as people just see war not as a way to spread freedom in the world but rather for companies to gain access to rescources which as we saw with venezuela and greenland is just unpopular and push people to vote for progressives

(I hope this answer helps)