You can do it with processors (https://www.elastic.co/guide/en/beats/filebeat/current/drop-fields.html). Also you can comment out the add_host_metadata (see below) option.
processors:
- drop_fields:
fields: ["ecs.version", "agent.version", "agent.type", "agent.id", "agent.hostname", "input.type"]
# - add_host_metadata: ~
# - add_cloud_metadata: ~