"final coup de grâce" is a pleonasm in this instance, but anyway, IMO he had no choice but to hold his cards for the apotheosis. This whole thing was a sting operation from the start. The aim was to uncover the traitors and by doing so, he had to let them commit their crimes to the full extent, so it would be obvious for all, even the normies. Take the electoral vote counting for example. At the rally outside the Capitole, while talking about Pence and his role during the counting process, Trump said that "it takes courage to do nothing". At that moment, he knew VP had the power to resend the fraudulent slates of electors to the States for recertification. Yet, VP did not do that, even though it would have been rightfully justified. Rather, he let the Congress members certify the results, even though they all knew it was fraudulent. The plan was to expose the traitors, by letting them commit the crime. The majority certified the fraudulent slates. We must expect happenings at the very last moments. The 19th of January is popcorn day btw.