Cache corrupted, e.g.:
May 26 12:34:39 KingNAMSBackup kernel: [ 65.314493] BTRFS error (device dm-0): parent transid verify failed on 1034009296896 wanted 390013 found 389928
May 26 12:34:39 KingNAMSBackup kernel: [ 65.315184] BTRFS error (device dm-0): parent transid verify failed on 1034009296896 wanted 390013 found 389928
May 26 12:34:39 KingNAMSBackup kernel: [ 65.317345] BTRFS error (device dm-0): parent transid verify failed on 1034009296896 wanted 390013 found 389928
May 26 12:34:39 KingNAMSBackup kernel: [ 65.317414] BTRFS info (device dm-0): no csum found for inode 263 start 1695498240
The error even indicates that the cache device doesn’t honor FLUSH commands. If possible I’d be interested in what kind of hardware it is.
To recover best reset the whole thing and recover from backup storage like you did in Urgent! System Disk Failed - #5 by KingNAMS
If you don’t want cache corruption each time the power fails consider using different hardware as cache device.