Gilgul destroys the mind of the person and their avatar.
That notably does not prevent you from resurrecting something very similar to that person. If you gilguled a mage, and then tried to resurrect them, it would be much harder, sure. You would have significantly more failures. But you could get someone similar to that mage. Like, every single EXEMPLAR is in effect a resurrection of an ancient heroic figure. The chances that Achilles's original avatar was floating around when Piero was made is... pretty low.
The entire point of gilgul is to remove corrupted avatars from circulation, making resurrection more difficult is a side effect.
To build on that, the thing is, you can't channel qlipphotic spheres through a non-inverted avatar. So if you resurrected a gilguled Technocrat or Traditionalist with a perfectly fine avatar, you would get someone with... possibly a significant degree of personality change and a damaged capability to do Enlightened Science/cast True Magic, but still quite similar to that person in question. It's quite possible that such a resurrection might lead to someone with severe enough damage that they can't act as a mage anymore, which is unfortunate. Such people tend to either hit the books a lot in the hopes that they get Awakened again via primer (which happens pretty often) or end up retiring, getting any sensitive memories willingly removed (the nice thing about erasure of memory is that it's much easier with a consenting party to do a clean erasure), and ending up in an influential but mundane job which the Technocrats or Traditions need people in.
If you resurrected a gilguled Nephandus, you'd end up with someone who has their very nature rebelling against their existence. It's not going to be Fun Times. It is exceedingly unlikely a gilguled Nephandus who gets resurrected will come back with magical ability, and the entire point of bringing someone back is because mages are rare and hard to acquire. Like, instead of wasting time on a has-been who demonstrably fucked up and got himself captured
alive for gilgul purposes, you could find a promising candidate and tutor them in the dark arts instead, which takes much less time and requires fewer spheres. The main reason you might want to risk a resurrection after the person's original avatar is unavailable/their information pattern has degraded sufficiently/etc etc is to bring back an experienced mage who knows what they're doing, and that's harder for Nephandi. Turns out seeking the destruction of all things makes it harder to come back from destruction.
And the term 'braintape' is kind of misleading. In PQ, the Technocracy finds accurately emulating brains hard. The Progenitors and ItX have adopted the idea of the brain as quantum computer to explain why NWO agents and Syndicate personnel can often manage predictive/analytical feats far exceeding even high-end computers with far more on-paper processing power. So a resurrection is generally either done with a much higher-resolution than just a mere copy of someone's memories, whether it's with a preserved corpse or with a very high-resolution map of the user's brain. These stored templates are refreshed every so often at Technocratic facilities, but they start degrading very quickly, and obviously can't be refreshed when someone is dead. Outside of very high-ranking individuals (who almost certainly have a
dedicated team and Devices to keep these templates updated every few days or hours, i.e. a Mind/Corr/Prime effect to soul jar them at the moment of death), these templates are highly lossy and fragile (which is why the Technocracy much prefers near-immediate resurrection with the actual corpse around)
Gilgul or Mindwipe would fuck the victim up to the point where you can't use them to verify the template. This means they're using a technique which generally produces beta-levels or gamma-levels and trying to upscale the resolution of the resulting brain template that they get an alpha-level. For a videogame analogy, the Technocrats doing a resurrection on a damaged braintape template are basically looking at screenshots and a handful of videos of the new Wolfenstein games, a copy of the script, and a copy of
Wolfenstein 3D, and then trying to recreate
Wolfenstein: The New Order more or less exactly.
You can imagine how easy this is going to be.
