First of all, abuse and breaking oath of office is not nescessarily criminal.
Second of all, charges did not matter to Republicans, they would not convict Trump no matter what.
In first impeachment some Republicans admited that Trump abused office but the excuse not to convict was that voters ought to make the descision to remove him (which they did).
In second impeachment the excuse was that Trump already left office so removal is moot.
None of that means that Impeachments are without consequence, they still have political and historical implications.