STOP FLYING the drone until this is fixed.
This assumes the
mini 2 is built in a similar way to the mavic mini.
In the Mavic Mini two screws hold the arm to its pivot, one screw is on/in the top of the arm the other screw is on/in the underside of the arm.
Once these screws are removed the arm will, WITH CARE AND WITHOUT FORCE, slide off the pivot, by
not a lot so but maybe by 1cm OR LESS. ( For the photo that will follow I did it with the arm in the closed position.)
The black thing is the pivot.
WITH CARE you can hold the arm SLIGHTLY to one side, as needs be, and check if the 3 screws that hold the pivot to the drone's body are loose, hopefully they are. If they are, nip them up but bear in mind they are tiny and screwing into plastic so do not use a 10ft lever to tighten them.
If that was the problem them refit the arm to the pivot and refit the screws. You would probably take longer to read this post than it would to do the job.
If the screw holes in the body have been stripped than you have bigger problems, possibly irrepairable or needing a new middle shell. If the pivot is broken then the drone needs to be opened, to allow removal of the motor wires and the fitting of a new pivot followed by the reattachment/ resoldering of the wires.