Maybe they got something/leverage on Panama President?
If by leverage, you're talking about the ability to ruin or kill him at a moment's notice, sure.
During the Cold War, the US
They have a sophisticated system of intelligence, influence, and control in the region, such that any opposition to the US is better thought of as "controlled" or "managed" opposition, than actual opposition.
Besides which, China can hardly defend any South American leader from the US. It doesn't have the intelligence chain and it doesn't have the blue water navy necessary to be a viable protector. This is why, push comes to shove, South American leaders will always bend the knee. It's just a matter of how much tolerance for risk they have - and in this case, we found a leader whose tolerance for risk is rather low.
People are cheering the collapse of the US too early. The imperial core might be in trouble, but the fact is, the US still has a lot of power, influence, and control around the world. Trump is just more willing to make use of that power than Biden was - he's the sort of president to abuse it to the limits.
Of course, whether any of this can save the US empire is a different story, but whatever the result, Trump 2.0 is going all out.