No longer should anyone in their module directly do something to a model and save it. They should always go through a service in the module owning that model, that makes sure everything is done correctly. So services.py and selectors.py works as a public API for the module, while the models are internal. Avoids having lots of other apps/modules depending on your app's internals.
> No longer should anyone in their module
> they should always go through a service
Weasel words and opinions-as-fact. Come back when you have a way to show that your approach gives any actual benefit.
"incomprehensible and slow". To whom? How slow? What about your approach makes it faster?
A sibling comment pointed one important aspect: Django Querysets are lazily evaluated, I find it really hard to believe that having a layer that constant marshalls and unmarshalls the data through pydantic can make anything faster than not having to fetch any data until you really need it.
But aside from that you are just adding another layer of abstraction that does not give any benefit when all your models are managed by Django already.