Generally, Fail-PU errors mean that the internal chip, the eMMC chips, has failed. Since you mentioned that you have tried many different RUUs and they all failed, I'm leaning towards a failed eMMC chip.
Essentially, it means your phone is now borked.
However, if your phone has S-OFF, you can try extracting the ZIP file and then removing the NFC file, then re-zip it. After that, put it in your phone and flash it as normal. If you remove the nfc file, it won't flash the NFC part of the update. I don't know if this would work, but you can try.