Most of the "OOP" code I've seen recently is made mainly of static functions organized in classes with little or no state, instantiated and injected by a DI con

Most of the "OOP" code I've seen recently is made mainly of static functions organized in classes with little or no state, instantiated and injected by a DI container in the name of flexibility. So I'd say that, in some sense, it's much less in vogue than it was fifteen years ago.