Mythologically-speaking? When it's described, valkyries are chosen from mortals and given the job (a bunch of the Eddas) or they're literally the children of two gods that fucked (Wagner). Assuming we're talking the Abrahamic type, angels were poofed into existence by a supreme god, no sex involved. You can see which of these fits Savarra better, I trust.
Also, valkyries kind of have fighting as their whole Thing, whether it's going out and kicking ass on their own or finding the worthy and bringing them to Valhalla to train to kick even more ass (and party) until the end of the world. Angels in most depictions are a bit less hardcore and spend more of their time being intermediaries and may or may not actually resemble anything humanoid.
Just to add to this, Savin has said that if you take Lumia's offer and have a penis,
you'll keep it but you will gain massive Femininity so you'd end up classed as Shemale or Hermaphrodite depending.
And while he didn't give a number, the Valkyrie TV will give you Femininity 'out the wazoo' so I'd imagine the answer to how much Femininity is 'All the Femininity'.