USAmerica now only has experience fighting against much weaker opponents. Almost everyone who remembers WW2 is dead.

When confronted with slightly more competent weak opponents (e.g. Taliban), the US military performs far more poorly. This poor performance worsens sharply as enemy competence scales.

Full-scale war with near-peer or peer adversaries? USA is SOL.

But aside from the loud-mouthed war hawks or perma-doomers on YouTube, I don't think anyone in the US or China (or Russia, for that matter) with decision-making power really has the appetite for direct open conflict, since it means the end of all things.

Expect more proxy wars like Ukraine...