Slim4 + PSR14 along with modular archiitecture

I started recently some e-commerce project and try to achieve strictly modular separation.
It’s kind of tricky as different modules interchanges its data repeatedly and you can not avoid (at the first sight) of injection for example “commerce” article service within let’s say “accounting” invoice service.
Even if it is just injection it breaks proper code separation and couples badly two different business logic.
On the other hand it is kind of unavoidable so I started thinking of using events as “intermodular” means of communication.
Does anybody have any experience on it?