I think you either need a better sex ratio if you have room for more ducks or you should rehome the female -- it is always easier to rehome a female than a male
Then you have to break the behavior of the attacks. I have an all drake flock that has got hormonal this spring and had lots of squabbles. The two muscovies have sorted things out although there were fights with wings flapping and feet raised sorting things out. My little pekin has sorted out his relationship with the muscovies after spending 6 weeks sleeping in a dog crate -- originally in my house but he wasn't happy so I moved the dog crate to the coop and that was perfect for him. He was out with the meanie muscovies during the day and all is now well. Unfortunately, my other pekin has now decided he wants to be the alpha male and has started attacking the alpha male muscovy. The pekin doesn't learn that he cannot possibly win a fight as the much larger and more muscular muscovy can easily stand on him or even turn him on his back and stand on him. The pekin keeps going for the muscovy's throat. Back in January, the pekin used to turn his back in a "I'm not fighting" pose when the other three were squabbling and so its really upsetting that he is now the aggressor. I have had to separate him because he, like yours Scoggins Family Homestead, is getting injured -- blood flowing and loss of tail feathers. So I am keeping the aggressor/injured pekin in his own dog crate in the coop at night, and in the coop -- outside of his dog crate -- during the day when the other drakes are free ranging. He is only out with the others when they are supervised and he basically needs to sit by me and stay there while the others get on with ducky business around him as he has not yet learnt that he must not attack the bigger muscovy. It's only a week at the moment, but he will be managed like this until he learns. You may have to separate your injured drake in this way, too, Scoggins Family Homestead
My muscovies learned very quickly that they must not bite the smaller pekins [or people], the muscovy that is being attacked by the pekin is very good about ignoring it until he eventually loses patience or I put the pekin back in the coop. The second muscovy gets his chest feathers pulled out by the smaller Pekin who also thinks he should be alpha male when it comes to muscovies. The second muscovy has learnt to ignore the little Pekin and not to retaliate. Why my muscovies learn and my pekins don't is beyond me!!