I keep bouncing between two opinions:
1. There is so much evidence and so much criminality that they absolutely have to indict.
2. This country will never prosecute a president. It's not what we do.
On the federal level, The AG must weigh what crimes to charge (you cant charge them all because there are so many). So a determining factor must be potential community harm if they do not bring charges. The fact that trump continues to lead one of the two parties of the nation and that party has shown total fealty to him must move the AG to see potential harm into the future. And by his public statements he has gotten worse instead of more tame since leaving office. Federal cases are almost always bullet proof with 90% conviction rate. Perhaps that explains the delay there.
State charges would be nice. Trump's tactic throughout his term in office was the "firehouse of lies". It would be nice to see him deal with a firehouse of charges on state level.