Trading on sword and shield should work. The best times that work are normally on Friday or saturdays EST probably around noon
I’ve just had a check, and Deoxys isn’t compatible with Sword and Shield unfortunately 😔 I can trade one via Pokémon Home if that helps?
Jirachi, Mew, Genesect etc. are all compatible with Sword and Shield however, so please let me know if you’d like any others instead! 😊