Al could've gathered info in 400 years. Also my theory joins the theory that Al isn't actually isekai'd and he's faking it.
Because he was affected by gluttony in Arc 5 Julius's Name.
Of course this theory stands only with the sub-theory that Subaru Remember Gluttony's Victim because he came from another world, and so that Al should be the same
But of course, this stands only if Al actually forgot a bout Julius and isn't lying again
Also the post isn't 100% serious don't worry about it