Actually their trial delays are a function of protecting their rights. As the defense has to give discovery, especially of exculpatory evidence to the defense before trial. And the more evidence the DOJ discovers, the more they have to turn over. But it's not just the raw evidence, like video footage. They have to provide the evidence specific to the person being tried. In essence, they have to make a video reel showing all the footage they have on each of the 1,000+ defendants. All the statements they have specific to each of the 1,000+ defendants, including statements from newly arrested individuals.
As new evidence is still coming in, they have to delay the trial, so they can turn that new evidence over to the defense.