Today during the Nintendo Treehouse post-Direct event, Game Freak gave us some bad news: the new Pokemon Home app will have limits.
According to Game Freak live at E3, "players will be able to transfer their Pokemon from Pokemon Home, only if they are in the Galar region Pokedex [so old Pokemon are possible, but only if they are in the new game]." They go on explain "so we thought about what the best selection of Pokemon to match the adventure to be." "More details" are coming later on this development, and they wanted to "let people know in advance" of this change. This puts the existence of a National Pokedex in Sword & Shield in complete jeopardy.
And that's it. Whelp, Home won't be the be-all-end-all of transfer apps.