At this point, he knows full well he lost. He's mostly just
trash talking now - which would be great in professional wrestling and some other businesses, but is not good when running the most powerful nation on earth.
I think a good many of his fans understand that this is just trash talk, but they think it is all good fun because they think one should never give an inch to one's enemies, even in defeat. Which again, is fine in some situations but has its limits in the current situation.
There is, I suppose and element of opportunism. If he gets enough people riled up, shotguns/spaghetti throws enough lawsuits and populist pressure, maybe he'll get lucky and make something happen. Almost certainly not, but he's having fun trying.
The main real concerns now are how soon he allows GSA to start the transition process, and whether or not any of the trash-talk motivates people to violence. I'm getting a bit less worried every day, mostly because the lawsuits have been such failures and because we've got some statements from the critical state governments stating that the elections are valid and the results will be followed. GSA may not be transitioning but the states are assigning delegates and the process of putting together Electoral College is moving along. The gradual grinding progress of that will allow people to slowly come to terms with the situation. (But they'll keep on trash talking and expressing denialism because they think that's fun.)