Hello,
If your phone is being detected by the pc but you’re unable to open the files inside then the issue could be the phone settings. On most phones when you plug it into a computer it asks if you want it to simply charge or for file transfer, sometimes called MTP (media transfer protocol). Your phone should have a popup like this when you plug it in, set it to file transfer and your pc should be able to get into your phone’s files.
If the issue isn’t with the phone settings try a different USB cable or a different USB port.
A workaround you can use is to use android’s “Nearby Share” sometimes called “Quick share”, so you can transfer files through wifi instead of cable if your pc is connected to a wifi network.
Hope this helps,
JC