Why not contributing the guides on ifixit and just keeping local copies? You can at least save a pdf copy?

How often will your internet go out? You could also cosnider an archiving solution for visited pages. Archivebox comes to mind.

Take a look at pocketbook devices. https://en.m.wikipedia.org/wiki/PocketBook_International

Will it work to find content on Lemmy easily by adding “Lemmy” to your Google query at the end?

Content is the second step I think…in my opinion copy what you deem useful und unproblematic?