Australia, Canada and Germany all have federal systems with “snap elections”—a federal system is not an obstacle.

And I think the lack of centralisation of US federal elections is part of what feeds distrust—when every state and even county does something slightly different, when state and local politicians have direct operational responsibility, when you have widespread adoption of voting machines — it is a lot easier for people to believe that fraud is happening. Compare that to the Australian system: federal elections are paper-based, hand-counted, and completely run by an apolitical/non-partisan federal bureaucracy (an independent federal executive agency), which does the same thing nationwide — narratives of distrust in election results find it harder to be accepted, because the system appears more trustworthy.