Corrupt EXT4 filesystem, backup superblock no dice

I am a novice linux user, for some time. I need some help with recovering a corrupted EXT4 filesystem. Ideally, I would like to recover the filesystem intact. The drive in question is 'sda'. The partition structure is given below. I have tried to mount partition 1, with backup superblock, but no dice. No idea on how to proceed from here. I am only attempting to fix 'sda1' now, as I will replicate what works on other partitions and drives. I have another 4Tb drive with the same issue. Thank you for your time. **Context**: I was using a Live USB to read/write to 'sda'. I was using it for a while, in this situation, when one day the drive was no longer accessible. I tried acessing from a proper installation of linux from a hdd, and now here we area. The drive 'sdb' is current linux installation drive. [ [Update] Remembered something. I had booted the disk from a test live cd and changed the permissions for all folders to rw across the 3 groups. Later, the drives were mounted(or tried to be mounted) on the original linux installation, with its own set of user & group rw permissions. I think, the lack of the correct permissions that it had expected to see of the files & folders, corrupted the superblocks.