In my first job after college, we had codebases that took both approaches: an OPP-y Java codebase with lots of inheritance and some FP-oriented codebases that used Scala case classes. As a novice, I definitely found the case class handling easier to browse and understand at the time.

The OOP stuff can be made a little easier to work with if your editor can show a lot of buffers at once and makes it easy to search through buffers. Trying to just flip through all of those files with tabs would have been really hard for me.