Hello @Mitigating the Damage
Being a client machine, the general recommendation when a "mess" happened with permissions, would be to re-image the computer. NTFS Permissions are very delicate when it comes to system, as even performing a takeover may break the ownership and permissions of certain system files or services.
All in all, I would see if the computer has restore points that can be used to timetravel to a moment without issues, but I would not put too much hopes.
Hope this helps with your query,
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