Sounds like you have a corrupt APFS file system, or possibly and more likely a failing Hard Drive.
Run DriveDx (free trial period) and post the complete text report here using the "Additional Text" icon which looks like a piece of paper on the forum editing toolbar.
You can also try running Disk Utility First Aid on the physical drive followed by the hidden Container. Within Disk Utility you may need to click "View" and select "Show All Devices" before the physical drive & hidden Container appears on the left pane of Disk Utility. Even if the First Aid summary says everything is "Ok", click "Show Details" and scroll back through the report to see if any unfixed errors are listed. If there are errors, then run First Aid again until they are gone. If after several scans the errors remain, then you will need to try running First Aid while booted into Recovery Mode (Command + R) or Internet Recovery Mode (Command + Option + R). If the errors still remain, then you will need to completely erase the whole physical drive (Intel Macs only) followed by reinstalling macOS & restoring from a backup. I doubt this particular error can be fixed, but it never hurts to try assuming the drive is healthy.
FYI, it is always advisable to post the exact model of your Mac. You can get this information by clicking the Apple menu & selecting "About This Mac".
