There is an example of exactly this use case in the current version of the Django (5.2) documentation: https://docs.djangoproject.com/en/5.2/ref/contrib/admin/#django.contrib.admin.ModelAdmin.save_model

class ArticleAdmin(admin.ModelAdmin):
    def save_model(self, request, obj, form, change):
        obj.user = request.user
        super().save_model(request, obj, form, change)