Models with parent::query not objects

Thanks, I am just coming to an older version of Code Igniter 3 and I understand most of the system, but I guess I just assumed CI_Model would auto map values to the model, but it seems like the people that developed this project treated models as a place to put function calls to a parent::query with huge SQL statements. Doesn't really seem like a real model that is mapped to an object and has a relationship with its associated data in the db.

I see CodeIgniter 4 is much more like what I enjoy using now. It seems I might have to use a different model class with Code Igniter and convert all the models in this code base or convert from CI3 to CI4 which is hard? I read in the documentation it is recommended to just start fresh and slowly port everything over?

Thanks