> like guarantees of correctness,
Yeah, no. I have to strongly disagree with this.
AWS's documentation about operating AWSs products and services I assume are correct and accurate.
If I follow their guides and end up breaking something because it turns out they forgot to tell me about something important, I would consider that a breach of warranty.
The only reason I can think of where documentation should be behind a pay/auth-wall is if it was generated specifically for your circumstances as part of some kind of solutions architecture or technical support process.