zfs raidz1 with encrypted dataset, two power-loss HDDs - data rescue possible ?

[Battlecake91]

Hello everyone,

first my setup: AMD Ryzen 5 5600G, AsRock B450m, 32Gig Corsair non-ECC, 5xWD120EFBX

steven@NAS:~$ zfs version
zfs-2.1.5-1ubuntu6~22.04.3
zfs-kmod-2.2.0-0ubuntu1~23.10.1

steven@NAS:~$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 22.04.4 LTS
Release:	22.04
Codename:	jammy

The 5 WD120EFBX runs in the raidz1 mode, I created it a year ago with
zpool create storage raidz1 -m /mypool /dev/by-id /dev/by-id ...

Then I created a encrypted dataset on this pool with:
zfs create -o encryption=aes-256-gcm -o keyformat=raw -o keylocation=xxx storage/mypool

Yesterday I heard some noises from one HDD, it restarted randomly - I checked the zpool status and every hdd was online and not degraded. So I checked it and heard that one HDD has a not that good power connector. But one other HDD on this power rail restarted too, sometimes. But as I said, nothing degraded. It started everytime after that again.
I held the power connector to stop it from restarting and shutted xubuntu down. After that I checked the cables, replaced it, started the NAS and waited before I boot if the HDD is restarting again. After some cable-testing, I thought everything is fine and restarted the NAS.

Now the zpool status tells me that there are not repairable data and I cannot decrypt my dataset.
I started a scrub and waited.

At the moment I'm at 27%, this is the output from zpool status:

steven@NAS:~$ sudo zpool status -v 
[sudo] Passwort für steven:  
  pool: storage 
 state: ONLINE
status: One or more devices has experienced an error resulting in data
	corruption.  Applications may be affected. 
action: Restore the file in question if possible.  Otherwise restore the 
	entire pool from backup. 
   see: https://openzfs.github.io/openzfs-docs/msg/ZFS-8000-8A 
  scan: scrub in progress since Tue Mar 19 00:51:29 2024 
	14.5T scanned at 283M/s, 12.4T issued at 243M/s, 47.3T total 
	0B repaired, 26.26% done, 1 days 17:48:42 to go 
config:

	NAME                                    STATE     READ WRITE CKSUM
	storage                                 ONLINE       0     0     0
	  raidz1-0                              ONLINE       0     0     0
	    ata-WDC_WD120EFBX-68B0EN0_5PKVARWF  ONLINE       0     0 1.08K
	    ata-WDC_WD120EFBX-68B0EN0_5PKVG20F  ONLINE       0     0 1.08K
	    ata-WDC_WD120EFBX-68B0EN0_5PKVGPTF  ONLINE       0     0 1.08K
	    ata-WDC_WD120EFBX-68B0EN0_5QKTYE3B  ONLINE       0     0 1.08K
	    ata-WDC_WD120EFBX-68B0EN0_5PKSL97F  ONLINE       0     0 1.08K

errors: Permanent errors have been detected in the following files: 

        storage/mypool@today:<0x0> 
        storage/mypool:<0x0>

If I try to mount the dataset - this happens:

steven@NAS:~$ sudo zfs mount storage/mypool
cannot mount 'storage/mypool': Eingabe-/Ausgabefehler

(It's german and says Input/Output error)

My big problem is, I have a Backup, but it is a few month old and at least I want to try to safe as many as possible and if it is just the directory structue to see what stuff is new, what is still in my backup.

Is there any way to get the dataset mounted again? Even with corrupted data?
I'm confused because before the shutdown, zpool status didn't show me any corrupted data or failed drives, the drive was online/running at the moment I shutdown.
Or is it because of the encryption? Some decryption necessary data corrupted. Would something change after the scrub or is it just time consuming and showing me that I lost this war?

I found some similar topics, one with a workaround where somebody tried to do a snapshot and recovers it or something...
It was this topic: #13709 , the last comment was the workaround but I don't really understand what to do.

[Battlecake91]

After a full scrub I still can't mount my dataset.

steven@NAS:~$ sudo zpool status -v
  pool: storage
 state: ONLINE
status: One or more devices has experienced an error resulting in data
	corruption.  Applications may be affected.
action: Restore the file in question if possible.  Otherwise restore the
	entire pool from backup.
   see: https://openzfs.github.io/openzfs-docs/msg/ZFS-8000-8A
  scan: scrub repaired 24K in 2 days 07:51:20 with 3 errors on Thu Mar 21 08:42:49 2024
config:

	NAME                                    STATE     READ WRITE CKSUM
	storage                                 ONLINE       0     0     0
	  raidz1-0                              ONLINE       0     0     0
	    ata-WDC_WD120EFBX-68B0EN0_5PKVARWF  ONLINE       0     0 1.57K
	    ata-WDC_WD120EFBX-68B0EN0_5PKVG20F  ONLINE       0     0 1.57K
	    ata-WDC_WD120EFBX-68B0EN0_5PKVGPTF  ONLINE       0     0 1.57K
	    ata-WDC_WD120EFBX-68B0EN0_5QKTYE3B  ONLINE       0     0 1.57K
	    ata-WDC_WD120EFBX-68B0EN0_5PKSL97F  ONLINE       0     0 1.58K

errors: Permanent errors have been detected in the following files:

        <0x122>:<0x0>
        storage/mypool:<0x0>

Is there any way to mount it even with the data errors or at least try to save some data? How can I prove that important data to mount is corrupted like headers or something?