Hello and thanks for reading.

There is many things to consider.

• With Cloud Function you are charged per request AND per CPU/Memory consumption (based on processing duration, to the upper 100ms). Cloud Endpoint pricing contain this per request charge and the processing (security checks, quotas and routing)
• If you don’t put a Cloud Endpoint layer, the traffic won’t be discarded and reach directly the Cloud Functions. In this configuration, your service will be effectively denied (target of DDoS attack!)
• Cloud Endpoint is a poor solution for DDoS protection, it’s better to consider it a protection for wrong/abusive usage, not for attack. Cloud Armor is dedicated to the DDoS protection and you will be able to use it with what is coming.