I am already experienced with the Microsoft Azure Device Provisioning Service, which enables my devices to register themselfes through e.g. Certificates in the Microsoft Azure IoT Hub. That makes of course enrollment of thousand of devices easier.
I have no experience in Google Cloud Platform and i have seen that there is MQTT Broker and an IOT Core Service within GCP.
But i didnt get it and it does not seem to be, that the IOT Core Service offers a similar functionality to the Microsoft Azure Device Provisioning Service.
Is this correct? Or how could i enroll lots of devices in an GCP IoT Architecture with automatic device registry and "distribution" over multiple IoT Core Services?
You could take a look at the Registeries and Device APIs to do the same. Having said that, one api call equals creation of one device.