I would like to point out that the burden of proof for a grand jury to return an indictment is only 51%, or "more likely than not." It's the same standard as a civil case.
Also, only the prosecution's case is presented. There is no defense, and no obligation to show the grand jury exculpatory evidence (unless they ask to see it).
Jury is 23 people at 100%. People do call out sick, but you need a minimum of 16 for a quorum. There must be 12 yes votes to return an indictment.
Almost all grand jury cases return an indictment as a result.
In the assumed forthcoming criminal case, the burden of proof is "beyond a reasonable doubt," and both sides will be presented.
Also note that the appeals will likely be granted for a former president, and they will likely take years. Trump could be president again before this is resolved.