You can backpropagate "modern" CS techniques like modularity an encapsulation to most ANY language like C or LISP or FORTRAN. But if have language and compiler support for these, it makes it easier and more reliable.
Of course there's a central data store. But that's okay.
https://www.cs.rit.edu/~ats/books/ooc.pdf
Many think C++ with its benefits and problems are relevant to OOP in C but not entirely. That's because they think C++ was about adding OOP to C. It wasn't. Stroustrup used safe, OOP languages like Simula that he wanted more of. He intended to leverage C's popularity and tooling but transform it into something with benefits of other languages. So, the result is C-like but not quite C and complex.
Just doing OOP in C, on other hand, is much easier and cleaner problem to solve. ;)