Is it a new SD card? Is it suitable - not all are?
Did you format in the drone, PC or
SC?
Is the SD in the drone or the
SC? or have you tried both?
if you connect your drone to a PC does it show 2 USB Drives?
It is often the case that when you connect the USB cable to the PC you will get a suggestion that there is a problem with both drives but then shortly after you should be told there are 2 drives lets say D: E:. This is a Windows driver issue and happens with M2 Pro and Air - at least for me. Depending on where you have designated storage one of those will likely be empty. Most users will designate their SD as primary storage so the internal storage will usually be empty apart from a folder structure produced by formatting via the controller. Always best to NOT format with the PC but via the controller. You will find your videos and photos in the appropriate folders in the DCIM folder in one of the drives.
You can have SD storage in the
SC as well and internal storage. Use File Explorer to look around the
SC storage which is a bit of a rats nest and has a lot of other DJI files other than videos and photos. Does your
SC gallery show any videos or photos corrupt or otherwise? have you set recording to cache on
SC storage or not?
You may have tried this but you should be able to do some test videos/photos with the props off see what goes.
I would get a different SD card inserted in the drone and formatted via the
SC. Should be possible to record some stuff in your home for testing.
I would also put a video ( anything ) on your SD card and see how it plays on your
SC and see if you can transfer it back and forth between drone and
SC see if it is designated corrupt or not. Could be your
SC software has got corrupted? Maybe the drone SD slot is dodgy? Try re-seating it and try another card in the drone, As previously suggested a refurb may not have been checked properly and have faulty SD connection or other issues. If all testing fails back to DJI with a complaint I'm afraid.
There are settings that designates what format the files are saved in maybe you should review those and try some others. Some (4K) will not play and possibly will be designated corrupt depending on where you play them. PCs and Macs don't like the same video files.