Broken SD card pieces are stuck in the card slot.

Take the camera to a repair shop, don't try to pry the pieces out, you will damage the sd card reader.

First of all you have to have good soft solder skills with thin. Find all screws. Specially the ones of the microphone. You have to dissasemble the shutter board from the main board. You will have to remove the solders. Are 12 or so. The main lens flex connector is a PITA. Takes around 1 to 2 hours to fix it. The lock of the sd card switch is bent all the time. Reshape it to the original position very careful. Is tiny.

You can try to clean SD card by blowing air into it or with some folded paper. This may help to sort out your problem.

Having the same problem with my Lumix GH5S. Unfortunately Panasonic has told me it will cost $250 to replace the slot (stuck in slot 2). I use the camera primarily for films so having 2 slots is one of the reasons I bought the camera. After taking it to the service center ( I live in Korea ), they had it for one week . I was told that the card is so jammed into the corner of the slot that the only option is to replace the part, which will unfortunately take up to a month to arrive in Seoul. However, if I'm able to fix it then I they'll just use the part for someone else. After getting the camera back and magnifying the inside with my phone camera, I can definitely see the chunk in the corner, and it looks literally packed in. The best part of the story is that it appears to be my friends SD card. Happy smiles all around.