Jack Smith gave Biden a roadmap, not to leave office if Trump wins, as it's an official duty to protect the constitution. His cabinet would support this, as would the DOJ. Kamala, being the Vice President won't certify the election...as its all protected by immunity.
Civil War might break out... but it would be worth holding this hard line until Congress, the Senate, and the Supreme Court are forced with fear as to the repercussions.