You can inject pk1 to pk7 files into a gen 8 save using pkhex, there is a projectpokemon 802 pokemon collection on the forum looks for that, as for gen 8 trading from CFW to Non CFW unit you can only do one by one, If you want to mass transfer from older gen like gen 6 and 7 games you can transfer them from a 3DS pokemon games into bank to transfer to home, requires a subscription.
Keep in mind if you inject older gen pk1- pk7 files directly into sword and shield , don't deposit them into home, as they have no home ID, not exactly sure what is the punishment for depositing pk1 to pk7 files pokemon into home from the switch end.