Multiple sources are saying that Trump has committed to leaving the White House on January 20 if the Electoral College confirms Biden's win. He also said, however, that he may not concede the election, saying, "It’s going to be a very hard thing to concede."
It's not a certainty, nor is it a legal requirement for the electors to vote exactly according to the popular votes in their homes states and the founders set it up that way in order to avoid mob rule and prevent the installation of a dictator who could win by promising things like forgiveness of all debts, free money, free healthcare, etc to the American people, thus bribing their way into office. The Constitution grants the electors the right to vote their conscious but also allows states to replace electors if they go against the wishes of the state. Electors cannot be fined or jailed for how they vote, only removed and replaced. In that case the vote of unfaithful elector would simply be replaced by the vote of the replacement elector.
But there is a limited period of time for replacing unfaithful electors.
He repeated claims that Republicans were not allowed to watch ballot counts which main stream outlets have said was false but which is actually nuanced. There were Republicans at the poll count centers but all of them were members of the anti Trump Lincoln Group. No pro Trump Republicans were allowed to watch the count and the Lincoln Group is widely for being even more extremely hateful of Trump than many Democrats are. Many Lincoln Group members have called for revenge against Trump supporters such as one who called for the homes of Trump voters to be burned to the ground.