Well, for starters, Trump has manifestly not conceded, at least not in word. He is still screaming about the "2020 Hoax", or "the most corrupt election in history", etc:
"What does GSA being allowed to preliminarily work with the Dems have to do with continuing to pursue our various cases on what will go down as the most corrupt election in American political history? We are moving full speed ahead. Will
never concede to fake ballots..." (emphasis added)
https://twitter.com/realDonaldTrump/status/133108696918362110
So you were already wrong in saying that Trump has "accepted defeat".
As for the rest of it, there was none of this crap: Obama cooperated with Trump in the transition period, and Clinton conceded the morning after.