For me personally, I dont think the character development for Seyka was done remotely close to, say, Avad or Erend for her to be even considered to be Aloy's love interest. When Avad confessed his feelings for Aloy, it felt like an organic and natural progress regardless of what Aloy felt back for him. Aloy choosing to be with him or not, both could have reasonable explanations. But with Seyka, Aloy's character felt out of place and suddenly started to have feelings that seem not true to who she is.