I like the quality of this SPF/DKIM/DMARC guide. This is the industry I started out in, and I actually wrote the guides for SendGrid, Amazon SES, and a few other email products. I don't mind saying that author has done a better job at this than me.
That being said, I see SPF/DKIM/DMARC guides like this pop up with some regularity, but users continue to have the same level of comprehension as before. I think the nature of this problem is not one that lends itself to being solved by guides. It's the sort of problem that a user is really only faced with once, which means that they're not getting the repetitions in to warrant any long-term comprehension.
I'm naturally biased here, but if you're onboarding users with SPF/DKIM/DMARC to your application, it's good if you can just get them setup with automation.