BEM is are methodology about atomic code design, it gives you a standards and guides how to simplify code maintaining.
Isn't this also what Tailwind, UNOCSS and the likes about?
Sounds like he have a problem where working in project using BEM, different team use it in different way (which I think as what to expect). And when components are involved, is CSS convention really the focus here?
edit: ok, I think I finally got your point...
How does BEM differ from OOCSS, AMCSS, SMACSS, SUITCSS?
Well... this thing feels like frontend framework with extra step.