How to best spend film to maximise Yanagis power.

I am a new player, in fact Yanagi is my only featured five star character. I want to make her as strong as possible. I have around 220 pulls saved up in film and around 30 from other sources. I was wondering if it would be better to get her W engine/ a constellation, or save for miyabi and maybe her w engine? I know there is no right or wrong answer, just wondering what everyone here thinks.