SSH KeyGen
pfSense has started creating missing SSH keys. SSH Startup will be delayed. Please note that reloading the filter rules and changes will be delayed until this operation is completed. @ 2022-05-01 12:55:10
That's normal whenever new keys are created. Which until 22.01/2.6 was every install or config reset.
You can recover the config from the pfSense install image as long as the partition is not completely destroyed, it gives you option before you install:
https://docs.netgate.com/pfsense/en/latest/backup/restore-during-install.html#recover-config-xml-from-existing-installation
Worst case you can cat the recovered config to the console from there and copy it out into a file.
There isn't a powershell script I'm aware of, but you can connect with ssh and run pfSsh.php playback changepassword admin, then enter the new password and confirm it.
Together with something like clusterssh or tabs with shared input in SecureCRT you could change a bunch to the same password all at once.
The only thing not backed up there would be packages pulled in directly from FreeBSD by specifying a different repo.
Those are not directly supported though
What did you actually have installed from FreeBSD?