But for real, the reason Trump looks like he's cucking out is simply because he is like most geopolitical actors, he wants to go through the path of least resistance over getting what he wants, he wants the most results with the lowest cost, The United States is not invulnerable from the effects of the war, it is incurring substantial costs even in just the 5 weeks of active war, both economic and political, and has the potential to become worse over if it goes hot again, it's why he's so insistent over negotiations and blockade - low cost, high potential results.
this is the trump playbook, make a show of strength and beat his chest, and hope it could force concessions or he quietly scales back the rhetoric for some compromises, it happened over tariffs, and it happened with Greenland.