Macbook Pro 16 Failed to boot after Big Sur update now I'm unable to mount the disk even in recovery mode

On reboot it showed the cannot boot from hard drive ? screen. I rebooted into recovery mode but it fails to mount the drive. I can see the drive there with the correct details. It says the following: Could not mount "disk0s2" (com.apple.Diskmanagement.dis enter error -119930868.) I googled the error but get lots of posts relating to external drives etc. Nothing in any posts I've come across has helped. When i run FistAid on the drive it get the following: Repairing Storage System Performing fsck_apfs -y -x /dev/disk02s2 warning: nx_block_count is 488475719, while device block count error: object (oid 0x1): o_cksum (0xbd26e8008dccb575) is invalid for object Checking the container superblock. Storage system exit code is 8. Storage system verify or repair failed. :(-69716) Operation failed. If i do "disk util apfs list" in terminal i get the following: Container ERROR -69808 APFS Container reference: disk1 Size (Capacity Ceiling): ERROR -69620 Capacity in use by volumes: ERROR -69620 Capacity not allocated: ERROR -69620 +-< Physical Store disk0s2 APFS Physical Store Disk: disk0s2 Size: 1894999998464 B (1.9 TB) I need some photos and files off the drive so if anyone can help it would be very much appreicated!