honestly something that confused me as a kid abt spd's ending was the fact that sky and bridge were promoted to red and blue respectively.. but z and syd weren't promoted to green and yellow. it might just have smthn to do with green being a more traditionally male ranger color (the writers/execs had to fight to have charlie be a-squad red bc she was a girl, and red is a traditionally male ranger color, too) in a pre-dino fury era of pr, so the disney higher ups didn't want to genderswap it
but now, in current year, i like to think that in-universe the girls were offered color promotions, but declined them bc they liked their colors as-is. like, i kinda have this hc that after bridge gets promoted again (or maybe retires idk), syd was offered red ranger promotion before z was, but she bowed out and said that z should have it. with that though, z insisted that syd was given second in command status if she becomes red, despite syd's number being 5 (and consistently declining color promotions)
and maybe if z decided to stop being an active duty ranger - while still being involved in spd, as it's her "something bigger" in contrast to jack's - syd's offered the red promotion again, and she declines once more. she asks if she can keep her color and have the status/leader role that comes with being red. she's approved for it, so she's the second pink ranger leader in pr history (with jen as the first in 2001)