In 2016 Trump had not remolded the GOP yet. He was surrounded by "traditional" republicans who weren't fully on board with his insane, vindictive, authoritarian impulse. Republicans in Congress were also skeptical of him, making resistance from the legislature much more likely.

In 2024 the entire Republican Party had evicted the non-MAGA people. Trump could staff everything with absolute sycophants. And there is no way that the Republicans in Congress will lift a finger to change anything.

Further, Trump had years of vindictive rage bottled up after losing in 2020. Every organization and institution he spent years raging about on Truth Social suddenly becomes his target. No actual governance. Just revenge.