Of course they are mad. The Republican strategy up until this point has been to attack the incumbent, but now the incumbent is no longer running for re-election. Trump literally doesn't know how to deal with this situation. His whole shtick is to attack the person currently in charge, but that doesn't do shit for him now.
A big part of why he lost in 2020, imo, is that he didn't have anybody to blame for all the bad shit happening in the country at the time. He himself was in charge and could only say "things will get worse under Biden", but people were sick of Covid fucking up our lives and the endless scandals that hit the news daily.
Wild huh? Hunter Thompson wrote about it once, and then it was in the movie version of Fear and Loathing in Las Vegas. Got warped around to what it is now.
There is a large chunk of the US population that believes this shit or things adjacent to it. 30% or so, I think. I've lost many people to it.
Check out Qanon Qausilties on Reddit. It's a cult, that's a mental illness, that's a political movement. Useful for the fascists. Very dangerous. Very sad.
It's a real substance the body makes, but it can also be synthesized. As such, people have taken it to try it out. Iirc it isn't even a fun high, so they started making up that children make "better" versions or something.