Is there a dominant route, or this is just another game where you must lose to get to the content?
In short: No, and no. There is a "evil" route. Where you get your own pet whore to train in how to pleasure men, while pleasuring men yourself. (And playing as said men in several scenes.) It's dressed up as a dom route, but it's just kabuki theater.
Basically. "Submitting" is the purpose of the game more or less. But you're not "losing" in most cases. Ex: You beat the boss of the stage, then turn around and go "UwU, C-Can I sucky wucky your dick senpai?!", you don't "lose" in the gameplay. (well, there ARE that too.) You just go "Yeah, I'm gonna go whore out!" after beating a level. More akin to a trainer game/SDT simulator where you can choose to do a RPG as minigame xP The descriptions and tags are WAY outdated.
There is the "pure" route. Where you are the hero, save the world and rescue your girlfriend. But it currently has practically 0 content. (in terms of porn reward) And there's no plans to add any outside of a "We've considered it.".
There ARE a few few scenes where you can choose to femdom another girl. But... those aren't finished. It's just a single picture. And like, half of them end with "Step aside! This is the job for a MAN!".