f2p evelyn vertical realistic?

im new to game so theres alot of thing i dont know and would like to know if:

- is it possible to make vertical evelyn work on entirely f2p

- how should i be spending the recources (if polychrome is suppose to be used on the banner character specifically only, then do i just sit on 21k polychrome always until evelyn comes up to pull?)

- do i upgrade pyro to the best of my abilities to carry my story mode progression? Or would i be wasting valuable resouces if i do so?

My goal is to beat the game and just laser focus on the character i wanna play

Greatly appreciate the helps!