Attorney General Merrick Garland has been criticized for the pace of the Department of Justice’s investigation into Donald Trump’s effort to overturn his election loss — and a new deep dive report shows he was often frustrated himself with its pace. Garland gathered his closest aides after he was sworn into office in March 2021 to discuss the possibility that evidence from the Jan. 6 investigation could point to criminal activity by the former president and his inner circle, but at that time it was “simply inconceivable” that Trump would recover politically so the attorney general proceeded wi…