I suggest using the no exclusives mod found at GameBanana (
https://gamebanana.com/mods/414750 ); it allows you to capture all pokemon in a single game apart from the opposite box legendary (Miraidon if you are on Scarlet or Koraidon if on Violet). Then use the encounter database in PKHeX to create yourself the opposite box legendary, as this will give you a legal pokemon.
As for the Charizard (and all other raid events), go to
https://projectpokemon.org/home/files/category/223-generation-9/ , you will find a list of events and inside each instructions to inject them into your save file using PKHeX.