I remain as shocked as you. When Trump was the candidate in 2024 I figured Kamala's victory was guaranteed. What I've come to realize in recent years is that USAmericans are fundamentally unwise. They really vote based on what they feel in the moment, hence why as the country gets worse, the elections keep flip-flopping.
Trump lost in 2020 because of Covid-19 and won in 2024 because of "grocery prices" and being the opposite major party to the current guy. The fact that he's an insurrectionist rapist conman who pioneered division and destruction just doesn't matter to them. The 2016-2020 term? The Pandemic he failed to maintain? Forgotten about. The embarrassments in the Republican-held congress? Most voters don't even recall them. How any of us live with this is beyond me. It's like being held hostage by self destructive parents.