I am playing Sword and breeding a Japanese Lucario I got from surprise trade for masuda method. I have tried several Riolu and a Ditto but they all have low breeding rates. Am I just unlucky or is this normal? This is my first time doing masuda method so I don't know what to expect.
First, Riolu can't breed. source After making sure your Pokemon can breed, their chance of breeding is determined by their species, original trainer, and oval charm. In your case, you can maximize that chance by breeding 2 Lucarios (of opposite genders) with different OTs and an oval charm. source