The difference is in intentional cruelty and the policy around how you deal with the problem. Housing minors that crossed without parents is not the same as forcibly and intentionally separating parents and children.

Immigration crisis causes are complex and have to do with the state of countries south of the US. You’d probably agree that Trump’s rhetoric didn’t incite “the caravan” yet they came anyway. Biden’s rhetoric against border crossing has been strict, he’s just not going to violate their rights.

Russia did have a preference for Trump and worked to help him (as detailed in the FBI’s report with lots of evidence to support this). Trump’s actions did not rise to the level of criminal conspiracy, but they did rise to the level of obstruction of justice (also detailed in the report), but ultimately that’s a determination that must be made by Congress to whom the report deferred.

This was a decision made based on an interpretation of fairness based on the OLC opinion (basically that it’d be wrong to assert guilt when you can’t charge). So it was left to Congress to interpret.