NIE cita previa

Hi everyone! A little background information: I am enrolled in a public spanish university (4 year grado studies). I come from a EU country.

I got my empadronamiento, but am struggling to get a cita previa to obtain NIE (Valencia). I was wondering if it's possible to try and get the cita previa in other province, for example Alicante or Castellon; or must it be in Valencia?

Other than this, I am not sure if I should apply for Certificados y asignacion NIE or for Certificado de registro de ciudadano de la U.E.? Whats the difference?

Thank you so much in advance!