That Shadowlands lore isn’t canon.
Literally just write it off and make it official.
Edit: Adding to my post-
How would they write it off? Doesn’t really matter. They could leave it intentionally vague. We don’t need a full top-down understanding of the universe, nor why certain things happen. Mystery would be better than Shadowlands being canon.
I think you’re wildly overestimating the extent to which they think they’ve screwed up.
Even when the gameplay folks were openly admitting that the borrowed-power direction turned out to be a mistake, the Story folks were giving barely any ground at all. They genuinely don’t think SL was that bad.
You are sort of getting what you want, kinda. They seem to be angling to have the veil seal the shadowlands back off so it is there… but it isnt.
Stuffing it back behind the curtain is as best as you can hope for.
Regardless of whether or not they’re aware, it would be a general boon for the lore if they wrote it off.
I don’t see it ruining lore more than it has some hair-brained schemes.
The Jailer got really lucky Sylvanas survived, Mueh’zala wasn’t discovered, and the Kyrian continued to pour souls into the maw-- even though the Kyrian know they’re dooming souls to the Maw. 
Kyrian and kyrestia are easily more evil than zoovy
They’re so willing to do this for actual good lore, it borderline just looks like ego and pride stopping them. They don’t seem to wanna admit that SL’s lore was bad until forced to. There were more references to SL in the main story of DF, usually small notes, like Alexstrasza’s library, until people complained that it was stupid and didn’t wanna see it lol.
It’s hilarious the one garbage piece they kept REMOVES METZEN’S FAVORITE HERO from the story right before he returns lmao.
I’m still voting for “everything from 8.3 to 9.2.5 was a Vision of N’zoth and we were unknowingly just doing a dance for him for a few years”.
More realistically, I do think it’s likely Blizzard will “clean up” the Shadowlands lore in the future to downplay it more, but they need to get the future storylines aligned first to keep it coherent. It’s difficult to just delete 2 years of the story - especially when it dramatically affects the status of major characters and of some events on Azeroth as well.
This is probably an unpopular thing to say (especially right now), but I don’t think everything about Shadowlands is bad. There are major issues, but there are also pieces worth keeping that will likely come up again in the future - and I wouldn’t mind keeping them (e.g. Denathrius).
It was N’zoth having a rare moment of losing his creativity and making a bland illusion so offensive even he got upset with it and destroyed it.
“Sorry even by my standards that went too far and had no taste, lets try again.”
I think Shadowlands would have felt a little less awful if it was purely the Azeroth-local veil before one leaves for the plane of death for good. Not the entire center for the plain of death, just the mechanisms put in place by [someone] to keep things orderly
Then it’d have seemed less Jarring that it was so Azeroth focused, it being artificial in the same way the ED is would have not felt as bad, and the Jailer probably wouldn’t have been written as being unintentionally everything bad that’s happened ever.
I mean, we took on what should have been a Pantheon level threat on somewhat even terms here, we really can’t be going back from that, the most equivalent fights like Sargeras had us being helped by equivallent strength entities and even that in mind it was still a big jump compared to Garrosh/Archimonde/KJ/Deathwing on the ol’ power scale.
We’re probably not far out enough from it yet. If sanity prevails, I think we’ll spend at least the rest of DF just sort of passively not acknowledging it, and then at some point some dev will give some sort of ambiguous half retcon statement like ‘what we saw in Shadowlands is not the full picture of death’ or something.
Honestly 100% agree with this thread because Shadowlands ‘lore’ is more damaging to the World of Warcraft story than beneficial.
Those are just some from the top of my head, but there’s many more.
Honestly would love if they retconned Shadowlands lore, by just over-writing it (Hey! Shadowlands did that to all the other lore, why not the other way around!?). 
I always found it funny how leading up to it, people seemed to push this idea we didn’t really know much about the afterlives. And it’s not wrong by any means- but we knew enough to know this def wasnt how it worked lol.
There is a fair concern that there’s too many races and sub culture for some in wow to make every afterlife. I don’t think anyone was actually even expecting all of them, or would have even if they did focus on the Azeroth specific ones. The Ancestral Halls of the Dwarves would be fun. The Light afterlife would’ve been too. The ‘shadow of the earthmother’ would’ve been much better at a fun new take on cosmic nature than Ardenweald.
Just have Sylvanas sneak out of the Maw and into Zereth Mortis and hit the Reshape Reality Button Zovaal juiced up. She rewrites reality by making it work how it did before BFA into Shadowlands, and undoes all the big stupids that ruined and killed off characters.
See, now that’s an act of redemption I can cheer her for.
Considering SL ends with effectively a big “hey there is a bigger bad guy out there”, they will probably use as a catalyst for WoW finally. Now if only Blizzard actually knew when WoW would end they might be able to plot it better.
It was only just a dream
Retcon the entirety of BfA as well. The damage that expansion did to characters, factions, races, and others in order to push that cringe story is better off forgotten.
I am of the opinion that : what is done is done.
I am not a fan of whole sale retcons unless it is adding something - like the Draenei being retconned added to the universe. I would not be a fan of just cutting out the lore we have experienced. There would have to be a VERY good reason - like renaming things named after the Cosby Crew or other bad actors. So far, the only reasons I see are a matter of taste.
I can’t sit and defend every plot point in Shadowlands as some great work of fiction. That does not mean it should be retconned out.
I agree it can make alot of more spiritual cultures seem as though they are wrong - but there are tons of afterlives we do not see. We are basically dealing with the covenants that run the place, there are other realms of death. I do not see it as so egregious, if you consider the background afterlives we do not see.
I delight in the lamentations of Arthas and Garrosh fans. They seem to be among the most upset about Shadowlands. It definitely puts a smile on my face, the way they cry about how those characters were handled. So, that makes me like Shadowlands even more. I had nothing but contempt for Arthas and Garrosh since I first encountered them. I always thought that the way they were worshipped by some fans was strange.
I could have just enjoyed their fate, but the tears from their fanboys made it extra enjoyable. If I was going to give Shadowlands a 6 out of 10, those fanboy tears add an extra point, and make it a 7.
In most cases, I would agree. But WoW has had so many retcons already at this point; what’s a few more?
And when the choices are to retcon or to continue with ruined lore, I say bring on the retcons.