Then it really depends what exactly you mean by OOP. Some people use the OOP features for modularity and structuring of the codebase, without any side effects/unmanaged mutation. Often they don't call it "OOP" then, but rather "a module system". But there isn't any theoretical distinction.

For example, I do _both_ Pure Functional Programming _and_ OOP (in the "module system" way) in Scala daily. And it works very nice IMHO, I encourage everybody to give it a try.

Use traits as interfaces for logical pieces of your business logic. Implement them in (case) classes which receive interfaces to other pieces of logic in their class constructor. Use a so called "Functional Effect System" like Cats Effect or ZIO to avoid raw side effects. And that's it, enjoy and profit.