That being said...

My skew is only ~13s on the WSL instance

And based on the sshd config's commented out defaults on the other device, that period should be 2m

So perhaps it is unrelated, after all 🤔

I have trouble updating my system. Can somebody tell me, what is going on? Couldn't find an issue on github for that.

$ cat $(nix-instantiate --find-file nixpkgs)/.git-revision
e99366c665bdd53b7b500ccdc5226675cfc51f45

sudo nixos-rebuild switch --upgrade
unpacking 2 channels...
unpacking 2 channels...
building the system configuration...
evaluation warning: The option `hardware.opengl.enable' defined in `/nix/store/cynw1547shxm7c3j7qi5jk6bgmvjwz3x-nixos-wsl/nixos-wsl/modules/wsl-distro.nix' has been renamed
to `hardware.graphics.enable'.
error:
       … while calling the 'head' builtin
         at /nix/store/jjmyd2jxv1s7awbjrxhysvr3z2filg7n-nixos/nixos/lib/attrsets.nix:1696:13:
         1695|           if length values == 1 || pred here (elemAt values 1) (head values) then
         1696|             head values
             |             ^
         1697|           else

       … while evaluating the attribute 'value'
         at /nix/store/jjmyd2jxv1s7awbjrxhysvr3z2filg7n-nixos/nixos/lib/modules.nix:1118:7:
         1117|     // {
         1118|       value = addErrorContext "while evaluating the option `${showOption loc}':" value;
             |       ^
         1119|       inherit (res.defsFinal') highestPrio;

       … while evaluating the option `system.build.toplevel':

       … while evaluating definitions from `/nix/store/jjmyd2jxv1s7awbjrxhysvr3z2filg7n-nixos/nixos/nixos/modules/system/activation/top-level.nix':

       … while evaluating the option `system.systemBuilderArgs':

       … while evaluating definitions from `/nix/store/jjmyd2jxv1s7awbjrxhysvr3z2filg7n-nixos/nixos/nixos/modules/system/activation/activatable-system.nix':

       … while evaluating the option `system.activationScripts.populateBin.text':

       … while evaluating definitions from `/nix/store/cynw1547shxm7c3j7qi5jk6bgmvjwz3x-nixos-wsl/nixos-wsl/modules/wsl-distro.nix':

       … while evaluating the option `wsl.extraBin."[definition 2-entry 1]".src':

       … while evaluating definitions from `/nix/store/cynw1547shxm7c3j7qi5jk6bgmvjwz3x-nixos-wsl/nixos-wsl/modules/recovery.nix':

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error: attribute 'nixos-enter' missing
       at /nix/store/cynw1547shxm7c3j7qi5jk6bgmvjwz3x-nixos-wsl/nixos-wsl/modules/recovery.nix:3:18:
            2| let
            3|   nixos-enter' = config.system.build.nixos-enter.overrideAttrs (_: {
             |                  ^
            4|     runtimeShell = "/bin/bash";
Command 'nix-build '<nixpkgs/nixos>' --attr config.system.build.toplevel --no-out-link' returned non-zero exit status 1.

Ah, no. Let me fix that and get back to you:

       error:
       Failed assertions:
       - The option definition `wsl.nativeSystemd' in `/etc/nixos/configuration.nix' no longer has any effect; please remove it.
       Native systemd is now always enabled as support for syschdemd has been removed
Command 'nix-build '<nixpkgs/nixos>' --attr config.system.build.toplevel --no-out-link' returned non-zero exit status 1.

restarting systemd...
Error: Failed to reset failed units

Caused by:
    Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.

[process exited with code 1 (0x00000001)]
You can now close this terminal with Ctrl+D, or press Enter to restart.

/mnt/wslg/distro/bin/nixos-wsl-recovery: /mnt/wslg/distro//nix/store/dih2wyarm9lyl006gnv7d869npkbgp6h-nixos-enter/bin/nixos-enter: /nix/store/ciarnmsx8lvsrmdbjddpmx0pqjrm8imb-bash-5.3p3/bin/bash: bad interpreter: No such file or directory
/mnt/wslg/distro/bin/nixos-wsl-recovery: line 9: /mnt/wslg/distro//nix/store/dih2wyarm9lyl006gnv7d869npkbgp6h-nixos-enter/bin/nixos-enter: Success

restarting systemd...
Error: Failed to reset failed units

Caused by:
    Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.

[process exited with code 1 (0x00000001)]
You can now close this terminal with Ctrl+D, or press Enter to restart.

/mnt/wslg/distro/bin/nixos-wsl-recovery: /mnt/wslg/distro//nix/store/dih2wyarm9lyl006gnv7d869npkbgp6h-nixos-enter/bin/nixos-enter: /nix/store/ciarnmsx8lvsrmdbjddpmx0pqjrm8imb-bash-5.3p3/bin/bash: bad interpreter: No such file or directory
/mnt/wslg/distro/bin/nixos-wsl-recovery: line 9: /mnt/wslg/distro//nix/store/dih2wyarm9lyl006gnv7d869npkbgp6h-nixos-enter/bin/nixos-enter: Success