>>58302724To correct myself, it's only roughly 1200-odd episodes from OS to end of Journeys, but that's still a considerable amount of time nevertheless. It's why I say you have to rid yourself of the overly restrictive notion that Ash is 10 forever because that's untenable with how much time must feasibly have passed, especially with Burnet getting pregnant and birthing a child from the span of mid-SM to Journeys when she reappears. It's much simpler to treat every episode as "1 full day", excepting the ones that have explicitly shown more than one day passing in them.
As for the meta knowledge, that is my own speculation, but it is a very reasonable assumption to make. Without May saying she's struggling in Johto, it would otherwise mean an experienced May goes all the way to Sinnoh in the middle of her own journey just to shit on a relative newcomer (Dawn) who's stuck in a rut of losses simply because she can.