Utilize the Cloud Natural Language API to extract metadata for categorizing the incoming cases, considering its ease of use and quick integration capabilities.

Develop a custom TensorFlow model leveraging Google’s BERT pre-trained model for high accuracy. After constructing and evaluating a classifier, deploy the model using Vertex AI for scalability and management.

Employ AutoML Natural Language to automatically create and assess a classifier, then deploy the model as a REST API for easy integration with existing systems, benefiting from its no-code approach and rapid deployment.

Implement BigQuery ML to design and test a logistic regression model for classifying incoming requests, and use BigQuery ML for predictions, taking advantage of its SQL-based interface for simplicity.