There is nothing saying that a pardon needs to specify which crimes are being pardoned, the pardon just needs to avoid any ambiguity. For example, here is the relevant bit of Nixon's pardon:
Now, THEREFORE, I, GERALD R. FORD, President of the United States, pursuant to the pardon power conferred upon me by Article II, Section 2, of the Constitution, have granted and by these presents do grant a full, free, and absolute pardon unto Richard Nixon for all offenses against the United States which he, Richard Nixon, has committed or may have committed or taken part in during the period from January 20, 1969 through August 9,1974.
So no need for Trump to confess anything. Just write himself a pardon that covers all crimes before {date}.
Though the question of if a president can pardon themself is a messy one. It will likely get challenged in court. Also, if the crimes have been pardoned, Trump can't plead the fifth to avoid testifying about an accomplices crimes. Which becomes messy if the pardon is being challenged.
Oh and pardoning those accomplices requires saying who they are. Which some of them might not like.
At this point, I think Trump's best options are:
- Get his lawyers focused on arguing for a comfortable house arrest because putting him in the general prison population causes problems for his secret service protection.
- Grab what money he can and flee the country. If there is somewhere safe for him to go to.
But both require Trump to admit that he's lost. So they seem unlikely he gets convicted.
