Yes, I'm aware of all that and it's not the first time WP has had to issue a correction to false statements or even make complete retractions at times for stories they've published in the past. Nor is it a shock other media outlets published the exact same quotes as they tend to use the same sources.
The quotes were attributed to Jason Fuchs, the deputy Secretary of State, whom Watson (the GBI Inspector) had briefed about the call - not actually made up by the paper itself - and were his understanding of what had been said. Other than those two quotes, the story itself remained the same.
The reality is, Trump was trying to put pressure on Watson to try and find accounts of signature fraud, specifically telling her to go back two years because signatures can vary over year to year and to look in Fulton County in particular because it's predominately black and democratic leaning.
He had no business contacting her in the first place, especially after the ballots had already been counted three times in Georgia - once by hand - with the exact same results and that a full audit was already underway. And that's not even factoring in all the other attempts by Trump, Lindsay Graham, Rudy Giuliani, etc. trying to overthrow the Georgia election results.