Hi @erickson78428
The fall may have loosened the camera connection, damaged the camera itself or damaged the camera's operating circuit on the motherboard.
Here's a teardown [https://www.youtube.com/watch?v=eS0FpLRtRo0|video] that shows how to open a Galaxy J2 phone (the variants e.g. core, pure etc are all basically the same) that may help.
The camera module is seen being removed at 4:47 minutes into the video.
If you suspect that the camera may be faulty, search online for ''Galaxy J2 Pure rear camera'', to find suppliers that suit you best.
If it isn't the camera module then the fall may have caused a problem on the motherboard affecting the camera circuit.
Here's a link to the [https://www.mobilerdx.com/2022/06/samsung-galaxy-j2-core-j260f-schematic-diagram-service-manual.html|schematics] that may help, if it is this