It’s definitely usable, but I think that I might prefer the sound of [name_f]Enya[/name_f]. [name_f]Enyo[/name_f] makes me think of the movie Ponyo, which is cute.
I like it. I think it is a name though that you would want to pair with a gendered middle eg. [name_f]Enyo[/name_f] [name_m]Graham[/name_m] instead of [name_f]Enyo[/name_f] [name_u]Blake[/name_u]
I really like Enyo. My only drawback with it is pronunciation. I believe the correct pronunciation is e nye oh, where as I think it would often be said en yo in the real world.