Haven't tried it yet, but I'm not sure if this would work in every situation. What happens if you set that marker to a model, but what happens if that model is imported in another file? Would that work?

I mean something like this:

# utils.py
from .models import MyModel


def update_model_timestamp(pk: int):
    instance = MyModel.objects.get(pk=pk)
    instance.timestamp = now()
    instance.save()

# models.py
from utils import update_model_timestamp

def foo():
    with bypass_hooks_for((MyModel,)):
        update_model_timestamp(pk=1)

yes, it's working also that way. I can testimony it's working in our project, running with cpython.
I'm fairly confident we can treat modules and their classes as singletons, the default import system is storing the modules in a global dict.
https://docs.python.org/3/faq/programming.html#how-do-i-share-global-variables-across-modules