Good day @lukas0 ,
Welcome to Google Cloud Community!
As of now, you need to reach out to Google Cloud Support in order to enable this feature in your Project. You can check the key note in this documentation: https://cloud.google.com/tpu/docs/system-architecture-tpu-vm#tpu-v4-config
You can use this link to reach out to Google Cloud Support: https://cloud.google.com/support
Hope this will help!