Not to be that myopic, but he never mentioned conceding to Biden:
"Now Congress have certified the results. [cut] A new administration will be inaugurated on January 20th. My focus now turns to ensuring a smooth, orderly and seamless transition of power."
"And to all of my wonderful supporters, I know you are disappointed, but I also want you to know that our incredible journey is only just beginning."
After a military intervention, an EO to prevent impeachment, and/or a DNI report for potential tribunals, his administration will certainly be new. And the transfer of power will be from the other side, to him or us. It ought to be seamless. And it will be a journey. I know I'm reaching, but nothing of his statements surprise me. Wouldn't be surprised if it was filmed weeks ago.