Partisan source? Maybe. But unfortunately the fact checkers have lost all credibility over the last few months by debunking things like, in the context of this article, hunter's laptop.
The federalist itself has spread a lot fake news over the years so you may want a better source to debunk the republicans in the state who literally ran the election who are saying it wasn't fraudulent.
Maybe you'll accept the credibility of the Republican lawmakers and election officials in Georgia who also consider those accusations of fraud to be baseless[0].