I’ve not spent enough time with bunpro to form any strong opinion, but there is definitely value in studying grammar (even in your native language). Tofugu just had a blog post that listed several useful resources if you aren’t a fan of bunpro.
Mimicry will only take you so far (otherwise we wouldn’t have English or 国語 classes in primary school).
Join us in the senryu thread for several examples where knowing all the words isn’t nearly enough to understand (or form) complex thoughts. Or simply try to explain when to use は and when to use が.
I just recommend holding off on serious grammar studies until you can read a bit. When depends on the individual, but in my case I didn’t feel ready until at least level 35 or so.