I have an Espeon on Pokémon sword, I breed him with Musharna to have Yawn, then taught Protect, but I don't seem be able to get him Dream Eater? Searching from here it says Espeon can learn it but I can't find how :(
Espeon historically learns Dream Eater via TM. However, Dream Eater is not a TM in Sword and Shield. As such, your set is not possible in Sword and Shield.