Re "Everybody always has their own personal continuity and canon that trumps everything"--forgive me if I said this before, but what works for me is to treat various eras at Marvel and DC as their own continuities, so for example, 90s Marvel is kind of its own world (and ends with the MC-2 future), early 00s Marvel is its own world (and ends with X-Men The End), and so on. Later retcons or reimaginings don't affect my readings of the older issues that way, and so I can enjoy everything! :)
There’s a good example, if that works for you!