who to rank up?

scxoxo

i'm pretty new to this game so i only have 5 4* champs, so i'm wondering if i should r3 either my rulk or proxima (both unduped), or r2 my other 3 champs (who are pretty bad) groot, iron fist, or howard the duck. should i spend my resources on ranking any of them up or should i wait for a god tier 4* since i'm not at a high level yet? i wanted to rank up proxima but i heard she's not as good unduped.

KittenPrime

proxima

Fhfjghhggggjfhfjg

Red hulk

Ajc10

Proxima

Sungj

Rulk is better for a new player, to utilize proxima to her full potential you have to intercept which is quite difficult for inexperienced players